path/filepath: deflake TestEvalSymlinksAboveRoot on darwin

On darwin, under load, it appears that the system occasionally
deletes the temp dir mid-test. Don't fail the test when that happens.

It would be nice to fix this in a deeper way.
See golang.org/cl/332009 for some discussion.

In the meantime, this will at least stop the flakiness.

Updates #37910

Change-Id: I6669e466fed9abda4a87ca88345c04cd7986b41e
Reviewed-on: https://go-review.googlesource.com/c/go/+/332009
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

Author: josharian

src/path/filepath/path_test.go

@@ -1469,11 +1469,16 @@ func TestEvalSymlinksAboveRoot(t *testing.T) {
 	// Try different numbers of "..".
 	for _, i := range []int{c, c + 1, c + 2} {
 		check := strings.Join([]string{evalTmpDir, strings.Join(dd[:i], string(os.PathSeparator)), evalTmpDir[len(vol)+1:], "b", "file"}, string(os.PathSeparator))
-		if resolved, err := filepath.EvalSymlinks(check); err != nil {
+		resolved, err := filepath.EvalSymlinks(check)
+		switch {
+		case runtime.GOOS == "darwin" && errors.Is(err, fs.ErrNotExist):
+			// On darwin, the temp dir is sometimes cleaned up mid-test (issue 37910).
+			testenv.SkipFlaky(t, 37910)
+		case err != nil:
 			t.Errorf("EvalSymlinks(%q) failed: %v", check, err)
-		} else if !strings.HasSuffix(resolved, wantSuffix) {
+		case !strings.HasSuffix(resolved, wantSuffix):
 			t.Errorf("EvalSymlinks(%q) = %q does not end with %q", check, resolved, wantSuffix)
-		} else {
+		default:
 			t.Logf("EvalSymlinks(%q) = %q", check, resolved)
 		}
 	}