Filter filepath googletest/ in script_wrapper.

Script wrapper should filter out googletest/ warnings and runtime
errors as those are not part of open-codecs scope.

Change-Id: Iffc52f68ffad6bd424116897188a0382ccde4610
Bug: b:198219807
Reviewed-on: https://chromium-review.googlesource.com/c/codecs/infra/+/3298389
Commit-Queue: Roberto Alanis Baez <alanisbaez@google.com>
Reviewed-by: James Zern <jzern@google.com>
3 files changed