Fix a dozen JS tests that were broken when using the command-line test harness (see bug 804834 comment 24 and 25). No bug#, r=evilpie on IRC.

--HG--
extra : rebase_source : 6ea3201dbd5ce97607b1d6847ee50d609dc3a91f
Bug 690970, part 1: unmark gray read barrier for weak maps. r=billm
Bug 690970, part 2: unmark gray read barrier for watchpoints. r=billm
Bug 690970, part 3: fix black-gray edges in weak containers at start of CC. r=billm
Bug 824670 - Validate Activity and Message hrefs during manifest parsing. r=mounir
Bug 824670 - Tests. r=mounir