[Gardening] inspector/audits/audits-panel-functional.html is flaky.

BUG=431152
TBR=dcheng@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/703213006

git-svn-id: svn://svn.chromium.org/blink/trunk@184941 bbb929c8-8fbe-4397-9dbb-9b2b20218538