This change provides fast code for a few special cases and calls the GenericBinaryOpStub for the rest.

It also changes the register allocation in the generation of lithium instructions to use fixed registers that are compatible with the generic stub. This allocation can be change once we use a more flexible implementation.

Finally, this change provides infrastructure to save double registers at safepoints, which is need to call the stub in deferred code.

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Review URL: http://codereview.chromium.org/6164005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6304 ce2b1a6d-e550-0410-aec6-3dcde31c8c00