cmd/go: convert TestCoveragePattern to the script framework

This test already runs in parallel, but still convert it to the
script framework so we can delete the testdata/src directory and
remove any ambiguity about which tests can run in parallel.

Updates #36320

Change-Id: I6470979bd8bad0631dc6ead0d4eb9c83878356e8
Reviewed-on: https://go-review.googlesource.com/c/go/+/212815
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

src/cmd/go/go_test.go

@@ -2193,22 +2193,6 @@ func TestCoverageImportMainLoop(t *testing.T) {
 	tg.grepStderr("not an importable package", "did not detect import main")
 }
 
-func TestCoveragePattern(t *testing.T) {
-	skipIfGccgo(t, "gccgo has no cover tool")
-	tooSlow(t)
-	tg := testgo(t)
-	defer tg.cleanup()
-	tg.parallel()
-	tg.makeTempdir()
-	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
-
-	// If coverpkg=sleepy... expands by package loading
-	// (as opposed to pattern matching on deps)
-	// then it will try to load sleepybad, which does not compile,
-	// and the test command will fail.
-	tg.run("test", "-coverprofile="+tg.path("cover.out"), "-coverpkg=sleepy...", "-run=^$", "sleepy1")
-}
-
 func TestCoverageErrorLine(t *testing.T) {
 	skipIfGccgo(t, "gccgo has no cover tool")
 	tooSlow(t)

src/cmd/go/testdata/script/cover_pattern.txt

+[gccgo] skip
+
+# If coverpkg=sleepy... expands by package loading
+# (as opposed to pattern matching on deps)
+# then it will try to load sleepybad, which does not compile,
+# and the test command will fail.
+! go list sleepy...
+go test -c -n -coverprofile=$TMPDIR/cover.out -coverpkg=sleepy... -run=^$ sleepy1
+
+-- sleepy1/p_test.go --
+package p
+
+import (
+	"testing"
+	"time"
+)
+
+func Test1(t *testing.T) {
+	time.Sleep(200 * time.Millisecond)
+}
+-- sleepy2/p_test.go --
+package p
+
+import (
+	"testing"
+	"time"
+)
+
+func Test1(t *testing.T) {
+	time.Sleep(200 * time.Millisecond)
+}
+-- sleepybad/p.go --
+package p
+
+import ^
+
+var _ = io.DoesNotExist

src/cmd/go/testdata/src/sleepy1/p_test.go

-package p
-
-import (
-	"testing"
-	"time"
-)
-
-func Test1(t *testing.T) {
-	time.Sleep(200 * time.Millisecond)
-}

src/cmd/go/testdata/src/sleepy2/p_test.go

-package p
-
-import (
-	"testing"
-	"time"
-)
-
-func Test1(t *testing.T) {
-	time.Sleep(200 * time.Millisecond)
-}

src/cmd/go/testdata/src/sleepybad/p.go

-package p
-
-// missing import
-
-var _ = io.DoesNotExist