Bug 1079640 - Fix some tests that fail when ES6 symbols are disabled. r=bz. DONTBUILD.

--HG--
extra : rebase_source : 7544ce2f0b8e2e59050ed87d7aea757e4702c834
extra : amend_source : 00f15dbe7b3f700fe3f6debede75c3b9a272e504