cmd/test2json: fix test log output containing test output

If test case framing appears in ordinary test output,
then test2json can get confused. If the fake framing is being
saved with t.Logf/t.Errorf/etc then we can already
distinguish it from real framing, and the code did.
It just forgot to write that framing as output (1-line fix).

If the fake framing is being generated by printing directly
to stdout/stderr, then test2json will simply get confused.
There's not a lot to do at that point (maybe it's even a feature).

Fixes #23036.

Change-Id: I29449c7ace304172b89d8babe23de507c0500455
Reviewed-on: https://go-review.googlesource.com/86238
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/internal/test2json/test2json.go

@@ -226,6 +226,7 @@ func (c *converter) handleInputLine(line []byte) {
 		if len(c.report) < indent {
 			// Nested deeper than expected.
 			// Treat this line as plain output.
+			c.output.write(origLine)
 			return
 		}
 		// Flush reports at this indentation level or deeper.

src/cmd/internal/test2json/testdata/issue23036.json

+{"Action":"run","Test":"TestActualCase"}
+{"Action":"output","Test":"TestActualCase","Output":"=== RUN   TestActualCase\n"}
+{"Action":"output","Test":"TestActualCase","Output":"--- FAIL: TestActualCase (0.00s)\n"}
+{"Action":"output","Test":"TestActualCase","Output":"        foo_test.go:14: Differed.\n"}
+{"Action":"output","Test":"TestActualCase","Output":"                Expected: MyTest:\n"}
+{"Action":"output","Test":"TestActualCase","Output":"                --- FAIL: Test output from other tool\n"}
+{"Action":"output","Test":"TestActualCase","Output":"                Actual: not expected\n"}
+{"Action":"fail","Test":"TestActualCase"}
+{"Action":"output","Output":"FAIL\n"}
+{"Action":"output","Output":"exit status 1\n"}
+{"Action":"output","Output":"FAIL    github.com/org/project/badtest     0.049s\n"}
+{"Action":"fail"}

src/cmd/internal/test2json/testdata/issue23036.test

+=== RUN   TestActualCase
+--- FAIL: TestActualCase (0.00s)
+        foo_test.go:14: Differed.
+                Expected: MyTest:
+                --- FAIL: Test output from other tool
+                Actual: not expected
+FAIL
+exit status 1
+FAIL    github.com/org/project/badtest     0.049s