Bug 1354947 - Update mochitest expectations for @keyframes merging. r=birtles

MozReview-Commit-ID: EKGVdKpybiQ

--HG--
extra : rebase_source : 864bbdd7f7c93ed51bf987e60660c7ece30ea8c8

layout/style/test/stylo-failures.md

@@ -36,7 +36,7 @@ to mochitest command.
   * test_webkit_device_pixel_ratio.html: -webkit-device-pixel-ratio [3]
   * browser_bug453896.js [8]
 * Animation support:
-  * test_animations.html [5]
+  * test_animations.html [1]
   * test_animations_dynamic_changes.html [1]
   * test_bug716226.html [1]
   * OMTA