regexp: skip long-running benchmarks if -short is specified

This CL helps race.bash finish in a reasonable amount of
time. Otherwise the Match/Hard1/32M benchmark takes over 1200 seconds
to finish on arm64, triggering a timeout.  With this change the regexp
benchmarks as a whole take only about a minute.

Change-Id: Ie2260ef9f5709e32a74bd76f135bc384b2d9853f
Reviewed-on: https://go-review.googlesource.com/c/go/+/201742
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/regexp/exec_test.go

@@ -665,7 +665,7 @@ func BenchmarkMatch(b *testing.B) {
 	for _, data := range benchData {
 		r := MustCompile(data.re)
 		for _, size := range benchSizes {
-			if isRaceBuilder && size.n > 1<<10 {
+			if (isRaceBuilder || testing.Short()) && size.n > 1<<10 {
 				continue
 			}
 			t := makeText(size.n)
@@ -688,7 +688,7 @@ func BenchmarkMatch_onepass_regex(b *testing.B) {
 		b.Fatalf("want onepass regex, but %q is not onepass", r)
 	}
 	for _, size := range benchSizes {
-		if isRaceBuilder && size.n > 1<<10 {
+		if (isRaceBuilder || testing.Short()) && size.n > 1<<10 {
 			continue
 		}
 		t := makeText(size.n)