Final CL to enable register allocation on x86.

This CL implements:
1) Resolution after allocation: connecting the locations
   allocated to an interval within a block and between blocks.
2) Handling of fixed registers: some instructions require
   inputs/output to be at a specific location, and the allocator
   needs to deal with them in a special way.
3) ParallelMoveResolver::EmitNativeCode for x86.

Change-Id: I0da6bd7eb66877987148b87c3be6a983b4e3f858
21 files changed