Clean up the redundant Int32Constant check which is covered by double case

BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/22815032

Patch from Weiliang Lin <weiliang.lin2@gmail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16282 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen.cc

@@ -6830,8 +6830,6 @@ bool HOptimizedGraphBuilder::TryInlineBuiltinMethodCall(
           } else if (exponent == 2.0) {
             result = HMul::New(zone(), context, left, left);
           }
-        } else if (right->EqualsInteger32Constant(2)) {
-          result = HMul::New(zone(), context, left, left);
         }
 
         if (result == NULL) {