This includes:
* Adding support for saving callee-clobbered double registers in Crankshaft code.
* Adding a new "HTrapAllocationMemento" hydrogen instruction to handle AllocationSiteInfo data in crankshafted stubs.
* Adding a new "HAllocate" hydrogen instruction that can allocate raw memory from the GC in crankshafted code.
* Support for manipulation of the hole in HChange instructions for Crankshafted stubs.
* Utility routines to manually build loops and if statements containing hydrogen code.

Review URL: https://codereview.chromium.org/11659022

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13585 ce2b1a6d-e550-0410-aec6-3dcde31c8c00