Bug 843626 GC: Rooting analysis failures in parallel array jittests r=terrence

--HG--
extra : rebase_source : a671dd445040312bdd464555f18844c993357129
Bug 843557 - Get rid of unneeded generic. r=sriram
Bug 843557: Revert part of 7547bf5fe166 (bug 843313). [r=kats]