Try re-enabling layout tests that crashed on try

Some WebSocket layout tests failed on the try bot but cannot be
reproduced locally. This CL will either reproduce the failures or find
whether they have been fixed.

BUG=339373

Review URL: https://codereview.chromium.org/175023002

git-svn-id: svn://svn.chromium.org/blink/trunk@167987 bbb929c8-8fbe-4397-9dbb-9b2b20218538