- Don't use SmiSub when overflow can occur. It asserts that overflow
  does not happen.

- Actually use CompareICs and signal to crankshaft whether or not smi
  code was inlined.

- Fix bug in CmpI where 64 bits were compared instead of 32 bits.

- Implement Throw, DeferredStackCheck, StoreKeyedFastElement in
  lithium backend.

BUG=
TEST=

Review URL: http://codereview.chromium.org/6312193

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6669 ce2b1a6d-e550-0410-aec6-3dcde31c8c00