MIPS: Convert UnaryOpStub to a HydrogenCodeStub.

Port r15506 (d0ea1f6)

BUG=

Review URL: https://codereview.chromium.org/18763003
Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15524 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
MIPS: Generate StoreGlobal stubs with Hydrogen.

Port r15512 (bdf9918)

Original commit message:
- Constants globals are inlined into Hydrogen code using code dependencies that invalidate the Crankshafted code when global PropertyCells or the global object change.
- The more general case generates code that is just as good as the hand-written assembly stubs on all platforms.

BUG=

Review URL: https://codereview.chromium.org/18277005
Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15525 ce2b1a6d-e550-0410-aec6-3dcde31c8c00