Bug 1503068 - update wpt metadata for html/semantics/ on android r=jgraham

Differential Revision: https://phabricator.services.mozilla.com/D10144

--HG--
extra : moz-landing-system : lando

testing/web-platform/meta/html/semantics/interactive-elements/the-dialog-element/dialog-showModal.html.ini

@@ -12,3 +12,7 @@
   [opening dialog with multiple focusable children, one having the autofocus attribute]
     expected: FAIL
 
+  [when opening multiple dialogs, the most recently opened is rendered on top]
+    expected:
+      if os == "android": FAIL
+