Update CheckBothSmi, CheckInteger32ValidSmiValue, CheckUInteger32ValidSmiValue, SmiAddConstant, SmiNot, AddSmiField and Test to support x32 port.
Adjust various constants, zero out the high 32bit of PC and FP for x32 port
Add X32 port into V8

Rebased with d35bc7c38c54e5cf51ff5d73831556f4dbad8884
Rebased with e9287e5b9addceb1cfa6642fd32c264fe03c6502
Rebased with 17811cd01a2aabc456a56677e1ca098dc8e740c8
Rebased with de57800048a2737614327d9803d4f17206354a11
Rebased with 6ac3afd74e2db3aeee456c9be474b29cbf1afce6
Rebased with 8ff59e1e370e0e6d244092290ea8ca8d23975e4f
Handled comments for X32
Rebased with e2be841e6dad4cdd0d5bc1216f52be844365e2b4
Added more boundary check for X32
Rebased with c248a0829468e346ab80497dbe07e9c942e6a723
Added OverwriteMode logic for X32
Use stack to save and reload arguments when allocation might fail
Rebased with 25c6cc8df3620bd3d38199b180617826a993253d
Rebased with 12f3d6a2d6727596531bca5ba3d7d1b31a4faa53
Rebased with d553b68cc0c301dba6952db4bbe68e0ebb498669
Refined deoptimization state handling
Ported https://chromiumcodereview.appspot.com/20070005/ and
https://chromiumcodereview.appspot.com/20298002 for X32
Fixed MacroAssembler::SmiShiftLogicalRightConstant