testing: consider -N suffix after benchmark name optional
A "-N" suffix is left out when GOMAXPROCS is 1.
Also match at least 1 space (\s+ instead of \s*), remove trailing '.*'
(it's a no-op), and make the test error message style more consistent
while here.
For #61515.
Fixes #70627.
Change-Id: Id0a17478ac31e2934a663dd0d3b1b37f24974989
Cq-Include-Trybots: luci.golang.try:gotip-plan9-386
Reviewed-on: https://go-review.googlesource.com/c/go/+/632655 Reviewed-by: Junyang Shao <shaojunyang@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>