Bug 1378076 - Part 4: add tests for moz prefixed properties. r=hiro

Add tests for following moz prefixed properties.

* -moz-user-select

MozReview-Commit-ID: 6X3iNYpc6kH

--HG--
extra : rebase_source : dc7d53801bab2b5563af3b35fd2f045b60000132

dom/animation/test/mozilla/test_moz-prefixed-properties.html

@@ -43,6 +43,9 @@ const testcases = [
   {
     property: "-moz-float-edge"
   },
+  {
+    property: "-moz-force-broken-image-icon"
+  },
   {
     property: "-moz-orient"
   },
@@ -66,10 +69,10 @@ const testcases = [
     property: "-moz-user-modify"
   },
   {
-    property: "-moz-window-dragging"
+    property: "-moz-user-select"
   },
   {
-    property: "-moz-force-broken-image-icon"
+    property: "-moz-window-dragging"
   },
 ];