Bug 1554777 - Disable test on Android because of flakiness and frequent failures. a=testonly

testing/web-platform/meta/css/css-backgrounds/border-image-width-006.xht.ini

@@ -1,3 +1,3 @@
 [border-image-width-006.xht]
-  expected:
-    if (os == "android"): FAIL      
+  disabled:
+    if (os == "android"): https://bugzilla.mozilla.org/show_bug.cgi?id=1554777