Layout Test webaudio/waveshaper-oversample-4x.html is no longer flaky

Looks like this was fixed by the v8 roll to 3.22.23.

BUG=311319
TBR=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/65173002

git-svn-id: svn://svn.chromium.org/blink/trunk@161552 bbb929c8-8fbe-4397-9dbb-9b2b20218538