Bug 1598726 - Disable browser_all_files_referenced.js on ccov due to permafail. r=jmaher

Differential Revision: https://phabricator.services.mozilla.com/D60349

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

devtools/client/framework/test/browser.ini

@@ -154,4 +154,4 @@ fail-if = fission
 [../../../../browser/base/content/test/static/browser_parsable_css.js]
 skip-if = debug || asan || (os == 'linux' && bits == 32) # no point in running on both opt and debug, and will likely intermittently timeout on debug
 [../../../../browser/base/content/test/static/browser_all_files_referenced.js]
-skip-if = debug || asan || bits == 32 # no point in running on both opt and debug, and will likely intermittently timeout on debug
+skip-if = debug || asan || bits == 32 || coverage # no point in running on both opt and debug, and will likely intermittently timeout on debug