Bug 992311 - Disable test_leaf_layers_partition_browser_window.xul everywhere. r=gbrown

layout/base/tests/chrome/chrome.ini

@@ -44,7 +44,7 @@ support-files =
 tags = openwindow
 [test_fixed_bg_scrolling_repaints.html]
 [test_leaf_layers_partition_browser_window.xul]
-skip-if = (!debug) || (toolkit == "cocoa") || (os == "linux") # Disabled on Mac and Linux because of Bug 992311
+skip-if = true # Bug 992311
 [test_no_clip_iframe.xul]
 [test_prerendered_transforms.html]
 [test_printpreview.xul]