cmd/go: adjust testsuite to add reraised panic message
A couple of tests generate different output due to CL 645916
for issue #71517.
Fixes #71593
Fixes #71594
Change-Id: Ifaeff4e9de8d881202bd9e6394c9b9cff8959596
Reviewed-on: https://go-review.googlesource.com/c/go/+/647495
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Commit-Queue: Ian Lance Taylor <iant@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Damien Neil <dneil@google.com>