runtime: fix SegvInCgo skip check

CL 390034 changed this throw message to add the goid, breaking the
match.

For #50979.

Change-Id: I52d97695484938701e5b7c269e2caf0c87d44d7a
Reviewed-on: https://go-review.googlesource.com/c/go/+/391139


Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>