Widen crash expectaion for webmidi tests to include other tests

The webmidi tests have gone from 2/4 being flaky/crashy to 4/4
being crashy, although there may be a new cause.

TBR=dpranke@chromium.org
BUG=282079

Review URL: https://codereview.chromium.org/34413005

git-svn-id: svn://svn.chromium.org/blink/trunk@160254 bbb929c8-8fbe-4397-9dbb-9b2b20218538