Bug 1649390 - skip test_remoteworker_launch_new_process.js when !e10s. r=dom-workers-and-storage-reviewers,asuth

Differential Revision: https://phabricator.services.mozilla.com/D81687

dom/workers/test/xpcshell/xpcshell.ini

@@ -9,6 +9,7 @@ support-files =
 [test_workers.js]
 [test_fileReader.js]
 [test_remoteworker_launch_new_process.js]
+skip-if = appname = 'thunderbird' # Thunderbird doesn't use e10s.
 # The following firefox-appdir make sure that this xpcshell test will run
 # with e10s enabled (which is needed to make sure that the test case is
 # going to launch the expected new processes)