Specifically:
-fixed a bug in CompareAndSwap that caused randomly occuring timeouts on MIPS boards.
-added gcc inline asm control push/pop instructions to correctly save/restore the reorder setting instead of simply assuming it should be enabled.
-reordered/optimized some instructions to utilize MIPS-specific pipelining features (branch delay slot).
-fixed improper usage of write barriers

BUG=
TEST=

Review URL: http://codereview.chromium.org/8413073
Patch from Gergely Kis <gergely@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9845 ce2b1a6d-e550-0410-aec6-3dcde31c8c00