Bug 1703712 - disable browser_bug1303838.js for frequent failures r=intermittent-reviewers,jmaher DONTBUILD

Differential Revision: https://phabricator.services.mozilla.com/D125343

dom/base/test/browser.ini

@@ -70,6 +70,8 @@ skip-if = verify
 [browser_timeout_throttling_with_audio_playback.js]
 skip-if = (os == "win" && processor == "aarch64") # aarch64 due to bug 1536566
 [browser_bug1303838.js]
+skip-if = 
+  os == "mac" && os_version == "10.15" && !debug # Bug 1703712
 [browser_bug1691214.js]
 skip-if =
   os == 'win' && bits == 64 # Bug 1692963