Make InterpolationRecord GarbageCollectedFinalized

Since InterpolationRecord has a RefPtr, it should be GarbageCollectedFinalized.

BUG=341032
TBR=ager

Review URL: https://codereview.chromium.org/208283005

git-svn-id: svn://svn.chromium.org/blink/trunk@169935 bbb929c8-8fbe-4397-9dbb-9b2b20218538