[release-branch.go1.21] runtime: don't let the tests leave core files behind
Also add a check that we didn't leave any core files behind.
For #65476.
Fixes #65478.
Change-Id: I30444ef43ad1a8cc1cacd3b75280f2128e104939
Reviewed-on: https://go-review.googlesource.com/c/go/+/525175
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
(cherry picked from commit
cffdfe8d2cabbe874bceaeed1eba92cc567be6db)
Reviewed-on: https://go-review.googlesource.com/c/go/+/560896