net/http: address comments from previous review

Move the test skip to use testenv.SkipFlaky and link to the Go issue.

Update #24826

Change-Id: I7a0ea3325ffcaa790b25f8cdc429fb52e96a41c7
Reviewed-on: https://go-review.googlesource.com/106636Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/net/http/serve_test.go

@@ -5630,8 +5630,7 @@ func runTimeSensitiveTest(t *testing.T, durations []time.Duration, test func(t *
 // read if it's already done one.
 func TestServerDuplicateBackgroundRead(t *testing.T) {
 	if runtime.GOOS == "netbsd" && runtime.GOARCH == "arm" {
-		// http://gnats.netbsd.org/53173
-		t.Skip("skipping to avoid crash")
+		testenv.SkipFlaky(t, 24826)
 	}
 
 	setParallel(t)