runtime/race: reject runtime fatal error in tests

runtime/race: reject runtime fatal error in tests

We expect those tests to fail with non-zero exit code, due to
intentional races, but we don't expect the runtime to crash.
Reject that.

Change-Id: Ic37987dabecde5f0703c031c49ce7f884a7b06a5
Reviewed-on: https://go-review.googlesource.com/c/go/+/270398
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>