Mark local failures in TestExpectations.

It's silly for everyone to see these failures locally when we
already have bugs on file documenting their existence.

I suspect these must pass on the bots, or we would have marked these as failing long ago.  They may both be clang=1 failures.

BUG=255714,231910

Review URL: https://codereview.chromium.org/26882004

git-svn-id: svn://svn.chromium.org/blink/trunk@159374 bbb929c8-8fbe-4397-9dbb-9b2b20218538