cmd/go: update test script for reformatted error message (fix long builds)
TBR=iant
Change-Id: Ic72af52e5ff8d28f8102c07b03e4930df61445ca
Reviewed-on: https://go-review.googlesource.com/c/go/+/358115
Trust: Robert Griesemer <gri@golang.org>
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com> Reviewed-by: Robert Findley <rfindley@google.com>