Fix a register assignment bug in typed array stores without SSE3 available.

Fix a register assignment bug in typed array stores without SSE3 available.

The old code used a separate HToInt32 instruction which had a wrong register
constraint for the input register which caused wrong result when the stored value
is used after a typed array store. (UseRegister instead of UseTempRegister) when no
SSE3 is available.

This change fixes it by replacing HToInt32 with the corresponding HChange
instruction which has correct register contraints.

TEST=mjsunit/compiler/regress-toint32.js
Review URL: https://chromiumcodereview.appspot.com/9565007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10891 ce2b1a6d-e550-0410-aec6-3dcde31c8c00