[release-branch.go1.13] cmd/doc: skip failing TestDotSlashLookup on Windows

This test was fixed by changing cmd/doc behavior in CL 204442.

Backporting that non-test code change is unlikely to be appropriate
this late in Go 1.13 release cycle. A failing test can cover up other
regressions, so skip this known failing test to fix the builder.

For #35236.
For #36181.

Change-Id: I07e795e75d7e37bc96ab68607d5d5cc9254342f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/223780
Run-TryBot: Dmitri Shuralyov <[email protected]>
Reviewed-by: Alexander Rakoczy <[email protected]>
Reviewed-by: Carlos Amedee <[email protected]>

Author: dmitshur

src/cmd/doc/doc_test.go

@@ -920,6 +920,9 @@ func TestDotSlashLookup(t *testing.T) {
 		t.Skip("scanning file system takes too long")
 	}
 	maybeSkip(t)
+	if runtime.GOOS == "windows" {
+		t.Skip("known Windows test failure on release-branch.go1.13; fix is in CL 204442 but requires non-test code changes unlikely to be appropriate for backporting this late")
+	}
 	where, err := os.Getwd()
 	if err != nil {
 		t.Fatal(err)