Add flaky inspector test to TestExpectations.

TBR=lushnikov@chromium.org
NOTRY=true
BUG=416846

Review URL: https://codereview.chromium.org/596223002

git-svn-id: svn://svn.chromium.org/blink/trunk@182575 bbb929c8-8fbe-4397-9dbb-9b2b20218538