os: skip TestRemoveAllRace on dragonfly

This test occasionally fails on the dragonfly-amd64 builder with
"directory not empty". Since that is the only platform on which we
observe these failures, and since the test had a different (and also
invalid-looking) failure mode prior to this one (in #50716), we
suspect that it is due to either a bug in the platform or a
platform-specific Go bug.

For #52301.

Change-Id: Id36c499651b9c48e6b8b0107d01f73d2a7b6bab8
Reviewed-on: https://go-review.googlesource.com/c/go/+/402155
Run-TryBot: Bryan Mills <[email protected]>
Auto-Submit: Bryan Mills <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: Bryan C. Mills

src/os/os_test.go

@@ -2429,6 +2429,9 @@ func TestRemoveAllRace(t *testing.T) {
 		// like it does on Unix.
 		t.Skip("skipping on windows")
 	}
+	if runtime.GOOS == "dragonfly" {
+		testenv.SkipFlaky(t, 52301)
+	}
 
 	n := runtime.GOMAXPROCS(16)
 	defer runtime.GOMAXPROCS(n)