Add blink_perf.web_animations target to Blink perf bots
Add blink_perf.web_animations target to Blink perf bots

This patch changes Blink perf bots to run the animation performance tests
with the Web Animations runtime flag enabled in addition to the existing
perf tests.

BUG=309981

Review URL: https://codereview.chromium.org/40233003

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@230883 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build