Add historical test for navigator.getUserMedia

This is only non-normatively defined, thus we should hope that
implementations will not continue to surface it.

mediacapture-streams/historical.https.html

@@ -8,6 +8,10 @@
   assert_false("webkitMediaStream" in window);
 }, "webkitMediaStream interface should not exist");
 
+test(function() {
+  assert_false("getUserMedia" in navigator);
+}, "navigator.getUserMedia should not exist");
+
 test(function() {
   assert_false("webkitGetUserMedia" in navigator);
 }, "navigator.webkitGetUserMedia should not exist");