virtual/implsidepainting/inspector/timeline/timeline-script-tag-1.html is flaky.

BUG=384956
TBR=

Review URL: https://codereview.chromium.org/331583004

git-svn-id: svn://svn.chromium.org/blink/trunk@176181 bbb929c8-8fbe-4397-9dbb-9b2b20218538