Bug 1580410 - Increase the timeout for browser_blockingMessaging.js by 2x in ccov tests

Differential Revision: https://phabricator.services.mozilla.com/D45546

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

toolkit/components/antitracking/test/browser/browser_blockingMessaging.js

@@ -1,6 +1,10 @@
 /* import-globals-from antitracking_head.js */
 
-requestLongerTimeout(6);
+if (AppConstants.MOZ_CODE_COVERAGE) {
+  requestLongerTimeout(12);
+} else {
+  requestLongerTimeout(6);
+}
 
 AntiTracking.runTestInNormalAndPrivateMode(
   "BroadcastChannel",