rate: skip TestLongRunningQPS on OpenBSD

time.Sleep is significantly oversleeping on OpenBSD, rendering this
test invalid.  Skip until that's resolved.

Updates #14183.

Change-Id: Ib0b79d198a0600454c5f74383d9933a2c05ddd2f
Reviewed-on: https://go-review.googlesource.com/19171
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

rate/rate_test.go

@@ -6,6 +6,7 @@ package rate
 
 import (
 	"math"
+	"runtime"
 	"sync"
 	"sync/atomic"
 	"testing"
@@ -163,6 +164,11 @@ func TestSimultaneousRequests(t *testing.T) {
 }
 
 func TestLongRunningQPS(t *testing.T) {
+	if runtime.GOOS == "openbsd" {
+		t.Skip("low resolution time.Sleep invalidates test (golang.org/issue/14183)")
+		return
+	}
+
 	// The test runs for a few seconds executing many requests and then checks
 	// that overall number of requests is reasonable.
 	const (