golang: tests: Fix traceback tests for Python ≥ 3.10

Python changed traceback output a bit:

- added '^^^^^^^' and '~~^~~'
- changed lineno of frame corresponding to __exit__ to be at line of `with ...`

-> Adjust to that by introducing a bit more generalized conditionals in
   assertDoc.

Here is, for example, how test_defer_excchain_traceback was failing on py3.11:

E           Failed: not equal:
E           Differences (unified diff with -expected +actual):
E               @@ -1,6 +1,7 @@
E                Traceback (most recent call last):
E               -  File "PYGOLANG/golang/__init__.py", line ..., in _
E               +  File "PYGOLANG/golang/__init__.py", line 103, in _
E                    return f(*argv, **kw)
E               -  File "PYGOLANG/golang/golang_test.py", line ..., in caller
E               +           ^^^^^^^^^^^^^^
E               +  File "PYGOLANG/golang/golang_test.py", line 1550, in caller
E                    raise RuntimeError("ccc")
E                RuntimeError: ccc
E               @@ -9,7 +10,7 @@
E                <BLANKLINE>
E                Traceback (most recent call last):
E               -  File "PYGOLANG/golang/__init__.py", line ..., in __exit__
E               +  File "PYGOLANG/golang/__init__.py", line 180, in __exit__
E                    d()
E               -  File "PYGOLANG/golang/golang_test.py", line ..., in q2
E               +  File "PYGOLANG/golang/golang_test.py", line 1548, in q2
E                    raise RuntimeError("bbb")
E                RuntimeError: bbb
E               @@ -18,14 +19,16 @@
E                <BLANKLINE>
E                Traceback (most recent call last):
E               -  File "PYGOLANG/golang/golang_test.py", line ..., in test_defer_excchain_traceback
E               +  File "PYGOLANG/golang/golang_test.py", line 1553, in test_defer_excchain_traceback
E                    caller()
E               -  ...
E               -  File "PYGOLANG/golang/__init__.py", line ..., in _
E               -    return f(*argv, **kw)
E               -  File "PYGOLANG/golang/__init__.py", line ..., in __exit__
E               +  File "/home/kirr/src/tools/go/py3.venv/lib/python3.11/site-packages/decorator.py", line 232, in fun
E               +    return caller(func, *(extras + args), **kw)
E               +           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
E               +  File "PYGOLANG/golang/__init__.py", line 102, in _
E               +    with __goframe__:
E               +  File "PYGOLANG/golang/__init__.py", line 179, in __exit__
E               +    with __goframe__:
E               +  File "PYGOLANG/golang/__init__.py", line 180, in __exit__
E                    d()
E               -  File "PYGOLANG/golang/__init__.py", line ..., in __exit__
E               -    d()
E               -  File "PYGOLANG/golang/golang_test.py", line ..., in q1
E               +  File "PYGOLANG/golang/golang_test.py", line 1545, in q1
E                    raise RuntimeError("aaa")
E                RuntimeError: aaa

golang/golang_test.py

@@ -1559,6 +1559,7 @@ RuntimeError: gamma
 Traceback (most recent call last):
   File "PYGOLANG/golang/__init__.py", line ..., in _
     return f(*argv, **kw)
+           ^^^^^^^^^^^^^^                                       +PY311
   File "PYGOLANG/golang/golang_test.py", line ..., in caller
     raise RuntimeError("ccc")
 RuntimeError: ccc
@@ -1579,9 +1580,11 @@ Traceback (most recent call last):
     caller()
   ...
   File "PYGOLANG/golang/__init__.py", line ..., in _
-    return f(*argv, **kw)
+    return f(*argv, **kw)                                       -PY310
+    with __goframe__:                                           +PY310
   File "PYGOLANG/golang/__init__.py", line ..., in __exit__
-    d()
+    d()                                                         -PY310
+    with __goframe__:                                           +PY310
   File "PYGOLANG/golang/__init__.py", line ..., in __exit__
     d()
   File "PYGOLANG/golang/golang_test.py", line ..., in q1
@@ -1596,9 +1599,11 @@ Traceback (most recent call last):
     caller()
   ...
   File "PYGOLANG/golang/__init__.py", line ..., in _
-    return f(*argv, **kw)
+    return f(*argv, **kw)                                       -PY310
+    with __goframe__:                                           +PY310
   File "PYGOLANG/golang/__init__.py", line ..., in __exit__
-    d()
+    d()                                                         -PY310
+    with __goframe__:                                           +PY310
   File "PYGOLANG/golang/__init__.py", line ..., in __exit__
     d()
   File "PYGOLANG/golang/golang_test.py", line ..., in q1
@@ -1611,6 +1616,7 @@ RuntimeError: aaa
 Traceback (most recent call last):
   File "PYGOLANG/golang/__init__.py", line ..., in _
     return f(*argv, **kw)
+           ^^^^^^^^^^^^^^                                       +PY311
   File "PYGOLANG/golang/golang_test.py", line ..., in caller
     raise RuntimeError("ccc")
 RuntimeError: ccc
@@ -1631,9 +1637,11 @@ Traceback (most recent call last):
     caller()
   ...
   File "PYGOLANG/golang/__init__.py", line ..., in _
-    return f(*argv, **kw)
+    return f(*argv, **kw)                                       -PY310
+    with __goframe__:                                           +PY310
   File "PYGOLANG/golang/__init__.py", line ..., in __exit__
-    d()
+    d()                                                         -PY310
+    with __goframe__:                                           +PY310
   File "PYGOLANG/golang/__init__.py", line ..., in __exit__
     d()
   File "PYGOLANG/golang/golang_test.py", line ..., in q1
@@ -1800,9 +1808,25 @@ def assertDoc(want, got):
     got = got.replace(udir_pygolang, "PYGOLANG") # ~/.../pygolang       -> PYGOLANG
 
     # want: process conditionals
-    # PY39(...) -> ... if py39 else ø
-    py39 = sys.version_info >= (3, 9)
-    want = re.sub(r"PY39\((.*)\)", r"\1" if py39 else "", want)
+    # PY39(...) -> ...   if py ≥ 3.9 else ø  (inline)
+    # `... +PY39` -> ... if py ≥ 3.9 else ø  (whole line)
+    # `... -PY39` -> ... if py < 3.9 else ø  (whole line)
+    have = {}  # 'PYxy' -> y/n
+    for minor in (9,10,11):
+        have['PY3%d' % minor] = (sys.version_info >= (3, minor))
+    for x, havex in have.items():
+        want = re.sub(r"%s\((.*)\)" % x, r"\1" if havex else "", want)
+        r = re.compile(r'^(?P<main>.*?) +(?P<y>(\+|-))%s$' % x)
+        v = []
+        for l in want.splitlines():
+            m = r.match(l)
+            if m is not None:
+                l = m.group('main')
+                y = {'+':True, '-':False}[m.group('y')]
+                if (y and not havex) or (havex and not y):
+                    continue
+            v.append(l)
+        want = '\n'.join(v)+'\n'
 
     # want: ^$ -> <BLANKLINE>
     while "\n\n" in want:

golang/testprog/golang_test_defer_excchain.txt

 Traceback (most recent call last):
   File "PYGOLANG/golang/__init__.py", line ..., in _
     return f(*argv, **kw)
+           ^^^^^^^^^^^^^^                                       +PY311
   File "PY39(PYGOLANG/golang/testprog/)golang_test_defer_excchain.py", line 42, in main
     raise RuntimeError("err")
 RuntimeError: err
@@ -21,6 +22,7 @@ Traceback (most recent call last):
     ...
   File "PY39(PYGOLANG/golang/testprog/)golang_test_defer_excchain.py", line 33, in d2
     1/0
+    ~^~                                                         +PY311
 ZeroDivisionError: ...
 
 During handling of the above exception, another exception occurred:
@@ -30,7 +32,8 @@ Traceback (most recent call last):
     main()
   ...
   File "PYGOLANG/golang/__init__.py", line ..., in _
-    return f(*argv, **kw)
+    return f(*argv, **kw)                                       -PY310
+    with __goframe__:                                           +PY310
   File "PYGOLANG/golang/__init__.py", line ..., in __exit__
     ...
   File "PYGOLANG/golang/__init__.py", line ..., in __exit__