Augment set of WPT tests for interpolation of transform lists.

This patch improves test coverage for the interpolation of transform lists. Specifically, the new tests cover:
* mismatched list lengths with a partial prefix match
* mix of exact and primitive (e.g. scaleX & scaleY --> scale) matches

These new tests fail in Chrome without the patch (https://chromium-review.googlesource.com/c/chromium/src/+/1372025) to implement the algorithm outlined in transforms spec (https://drafts.csswg.org/css-transforms-1/#interpolation-of-transforms), but pass when tested in Firefox version 64.0.


Bug: 918643

Change-Id: I65bfe5b3c13c2fb33b3d2b926dc153135b140a63
Reviewed-on: https://chromium-review.googlesource.com/c/1393460
Reviewed-by: Ian Vollick <vollick@chromium.org>
Commit-Queue: Kevin Ellis <kevers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619635}
2 files changed