Remove 1.3 MB of superfluous media files for LayoutTests

LayoutTests/media/media-file.js

 var audioCodecs = [
     ["audio/wav", "wav"],
     ["audio/aac", "m4a"],
-    ["audio/mpeg", "mp3"],
     ["audio/ogg", "oga"]
 ];
 
 var videoCodecs = [
     ["video/mp4", "mp4"],
-    ["video/mpeg", "mpg"],
-    ["video/quicktime", "mov"],
     ["video/ogg", "ogv"]
 ];
 
 function findMediaFile(tagName, name) {
     var codecs;
     if (tagName == "audio")
         codecs = audioCodecs;
     else
         codecs = videoCodecs;
 
@@ skipping 43 matching lines @@
     if (element)
         element.src = src;
 }
 
 function stripExtension(filename) {
   var lastPeriodIndex = filename.lastIndexOf(".");
   if (lastPeriodIndex > 0)
     return filename.substring(0, lastPeriodIndex);
   return filename;
 }