[release-branch.go1.16] testing/race: fixing intermittent test failure
Test NoRaceMutexPureHappensBefore in runtime/race/testdata/mutex_test.go
expects the second spawned goroutine to run after the first. The test
attempts to force this scheduling with a 10 millisecond wait. Following
a suggestion by Bryan Mills, we force this scheduling using a shared
variable whose access take place within the existing mutex.
Fixes #50832.
Updates #35745.
Change-Id: Ib23ec51492ecfeed4752e020401dd25755a669ed
Reviewed-on: https://go-review.googlesource.com/c/go/+/291292
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
(cherry picked from commit
aaed6cbced238030053df4e54f676a1d59df89d7)
Reviewed-on: https://go-review.googlesource.com/c/go/+/381034
Trust: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>