MIPS: Add support for arch. revision 6 to mips32 port.

Additional summary:
 - Introduce fp64 fpu mode into mips32 port required for r6.
 - Implement runtime detections for fpu mode and arch. revision to preserve
   compatibility with previous architecture revisions.

TEST=
BUG=
R=jkummerow@chromium.org, paul.lind@imgtec.com

Review URL: https://codereview.chromium.org/453043002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23028 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
More lazy deoptimization in Turbofan (binops, loads/stores)

Deoptimizing binory operations, (Load|Store)(Property|Named),
constructors.

This also fixes safepoint lookup to account for lazily deoptimized code.

BUG=
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/453383002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23029 ce2b1a6d-e550-0410-aec6-3dcde31c8c00