[dev.regabi] runtime/race: adjust test pattern match for ABI wrapper

Adjust the pattern matching in one of the race output test to allow
for the possible introduction of an ABI wrapper. Normally for tests
that match traceback output wrappers are not an issue since they
are screened out by Go's traceback mechanism, but in this case the
race runtime is doing the unwinding, so the wrapper may be visible.

Change-Id: I45413b5c4701d4c28cc760fccc8203493dbe2874
Reviewed-on: https://go-review.googlesource.com/c/go/+/278756


Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Trust: Than McIntosh <thanm@google.com>