Bug 1366956 part 3 - Update test expectations. r=heycam

MozReview-Commit-ID: 1MBPiLaNFHW

--HG--
extra : rebase_source : db06d228ef349d587f9b5b11bf0898a429176082

layout/style/test/stylo-failures.md

@@ -30,9 +30,6 @@ to mochitest command.
 ## Failures
 
 * Media query support:
-  * "layout.css.prefixes.device-pixel-ratio-webkit" support bug 1366956
-    * test_media_queries.html `-device-pixel-ratio` [27]
-    * test_webkit_device_pixel_ratio.html [3]
   * test_media_queries_dynamic_xbl.html: xbl support bug 1382078 [1]
 * Animation support:
   * SMIL Animation