If not all uses of arithmetic binary operation can be truncated to Smi, check if they can be truncated to Int32 which could avoid minus zero check
Fixed DoMulI on X64 to adopt correct operand size when the representation is Smi
Fixed DoMulI on ARM. Constant right operand optimization is based on Integer 32 instead of its representation.
BUG=
R=verwaest@chromium.org
Review URL: https://chromiumcodereview.appspot.com/22600005
Patch from Weiliang Lin <weiliang.lin2@gmail.com>.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16361 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
