Bug 1391823 - Disable dom/security/test/mixedcontentblocker/test_frameNavigation.html for frequent failures. r=jmaher

dom/security/test/mixedcontentblocker/mochitest.ini

@@ -24,5 +24,5 @@ skip-if = toolkit == 'android' || webrender # Android: TIMED_OUT; webrender: bug
 [test_bug803225.html]
 skip-if = toolkit == 'android' || (os=='linux' && bits==32) || headless #Android: TIMED_OUT; Linux32:bug 1324870; Headless:bug 1405870
 [test_frameNavigation.html]
-skip-if = toolkit == 'android' || webrender # Android: TIMED_OUT; webrender: bug 1424752
+skip-if = (toolkit == 'android') || webrender || (debug && (os == 'linux' || os == 'win')) # Android: TIMED_OUT; webrender: bug 1424752 # Bug 1391823
 [test_redirect.html]