runtime/race: be less picky about test run time

Currently, there are two regexps in the race detector output tests
that assume subtests will complete in < 1 second. This isn't necessary
and very occasionally fails (on builders that are probably very
loaded). Make these tests less picky about timing.

Fixes #50612.

Change-Id: Ib3f94d6c5dc37541dbeb06de71cf462a74af844b
Reviewed-on: https://go-review.googlesource.com/c/go/+/378581
Trust: Austin Clements <[email protected]>
Run-TryBot: Austin Clements <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: aclements

src/runtime/race/output_test.go

@@ -207,7 +207,7 @@ func TestFail(t *testing.T) {
 }
 `, []string{`
 ==================
---- FAIL: TestFail \(0...s\)
+--- FAIL: TestFail \([0-9.]+s\)
 .*main_test.go:14: true
 .*testing.go:.*: race detected during execution of test
 FAIL`}},
@@ -363,7 +363,7 @@ func TestPass(t *testing.T) {
 }
 `, []string{`
 ==================
---- FAIL: TestFail \(0...s\)
+--- FAIL: TestFail \([0-9.]+s\)
 .*testing.go:.*: race detected during execution of test
 FAIL`}},
 	{"mutex", "run", "", "atexit_sleep_ms=0", `