Backed out 4 changesets (bug 496923) for jsreftest failures on a CLOSED TREE.

Backed out changeset 55796a799ea9 (bug 496923)
Backed out changeset 05a46b5b3fec (bug 496923)
Backed out changeset 0fde7e7ba61c (bug 496923)
Backed out changeset 8dff0aaddd1c (bug 496923)