Bug 1429323 - remove calls to SimpleTest.expectAssertions() from media mochitests. r=bechen

MozReview-Commit-ID: GapLJjIGjmK

--HG--
extra : rebase_source : f9ea3059d2d0abce6caeb69d29e47c410731039d

dom/media/test/test_bug686942.html

@@ -15,10 +15,6 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=686942
 <pre id="test">
 <script class="testbody" type="text/javascript">
 
-if (navigator.platform.startsWith("Win")) {
-  SimpleTest.expectAssertions(0, 2);
-}
-
 var manager = new MediaTestManager;
 
 function onloaded(event) {

dom/media/test/test_seek_out_of_range.html

@@ -10,10 +10,6 @@
 <pre id="test">
 <script class="testbody" type="text/javascript">
 
-if (navigator.platform.startsWith("Win")) {
-  SimpleTest.expectAssertions(0, 10);
-}
-
 var manager = new MediaTestManager;
 
 // Test if the ended event works correctly.