[LayoutTest] Split animations-parsing.html into two tests

Currently it tests both style.animation and getComputedStyle.animation.
This CL splits the test into two tests, one for style.animation, and
the other one for getComputedStyle.animation such that each test is
minimal.

Bug: 772852
Change-Id: I3c3f43305497ffe9d91c4e3806efe2e65ff17806
Reviewed-on: https://chromium-review.googlesource.com/c/1378230
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616677}
2 files changed