testing: use monotonic counts to attribute races in subtests
This implements the approach I described in
https://go-review.git.corp.google.com/c/go/+/494057/1#message-
5c9773bded2f89b4058848cb036b860aa6716de3.
Specifically:
- Each level of test atomically records the cumulative number of races
seen as of the last race-induced test failure.
- When a subtest fails, it logs the race error, and then updates its
parents' counters so that they will not log the same error.
- We check each test or benchmark for races before it starts running
each of its subtests or sub-benchmark, before unblocking parallel
subtests, and after running any cleanup functions.
With this implementation, it should be the case that every test that
is running when a race is detected reports that race, and any race
reported for a subtest is not redundantly reported for its parent.
The regression tests are based on those added in CL 494057 and
CL 501895, with a few additions based on my own review of the code.
Fixes #60083.
Change-Id: I578ae929f192a7a951b31b17ecb560cbbf1ef7a1
Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-longtest,gotip-linux-amd64-longtest-race,gotip-windows-amd64-longtest
Reviewed-on: https://go-review.googlesource.com/c/go/+/506300
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>