The new gofrontend message matches other gofrontend error messages,
so adjust the test to accept it.
For #27938
For #51237
Change-Id: I29b536f83a0cf22b1dbdae9abc2f5f6cf21d522d
Reviewed-on: https://go-review.googlesource.com/c/go/+/416014
Run-TryBot: Ian Lance Taylor <iant@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com>