net: disable TestAcceptTimeout for now

It's too flaky and doing more harm than good.

Disable it until it can be made reliable.

Updates #17948
Updates #17927

Change-Id: Iaab7f09a4060da377fcd3ca2262527fef50c558d
Reviewed-on: https://go-review.googlesource.com/33330Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/net/timeout_test.go

@@ -151,6 +151,7 @@ var acceptTimeoutTests = []struct {
 }
 
 func TestAcceptTimeout(t *testing.T) {
+	t.Skip("flaky test; golang.org/issue/17948")
 	t.Parallel()
 
 	switch runtime.GOOS {