Bug 1448915 - Disable browser_bug579872.js on mac and linux !debug for frequent failures. r=gbrown

Differential Revision: https://phabricator.services.mozilla.com/D49403

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

browser/base/content/test/general/browser.ini

@@ -166,7 +166,7 @@ skip-if = (os == "mac") #Bug 1526628
 [browser_bug578534.js]
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_bug579872.js]
-skip-if = (verify && debug && (os == 'linux'))
+skip-if = (verify && debug && (os == 'linux')) || (os == 'mac') || (os == 'linux' && !debug) #Bug 1448915
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_bug581242.js]
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.