Bug 496923 - Allow update-test262.sh to copy directly from a test262 working directory, when (even local) cloning would be too slow.  r=terrence

--HG--
extra : rebase_source : 9d74cf9bd45425defcbfd70291545442f8f5f489
Bug 496923 - Remove js/src/tests/update-test402.sh as update-test262.sh subsumes it.  r=trivial
Bug 879376 - Remove a bunch of obsolete files from js/src/tests.  r=terrence