Bug 1383512 - Skip test_user_select.html on windows of opt and pgo. r…

…=gbrown

This patch skip the test_user_select.html test since windows build of
pgo/opt will fail this test sometimes on try.
This is temporaly solution until clarifying the reason of it.
(We track it on same bug).

MozReview-Commit-ID: BlwdoYxNTxP

UltraBlame original commit: 3a17b61bc3e83cfb7db6af894fb4e30bf3f11963

dom/base/test/mochitest.ini

@@ -787,7 +787,7 @@ skip-if = debug == true && toolkit == 'android' # Timing dependent, skip slow de
 support-files = file_title.xul
 [test_treewalker_nextsibling.xml]
 [test_user_select.html]
-skip-if = toolkit == 'android'
+skip-if = (toolkit == 'android') || (os == 'win' && !debug) # Windows is timing dependent(bug 1383512)
 [test_viewport_scroll.html]
 [test_viewsource_forbidden_in_object.html]
 [test_w3element_traversal.html]