Port inlined quick equality check for non-NaN to x64.

src/ia32/codegen-ia32.cc

Index: src/ia32/codegen-ia32.cc
===================================================================
--- src/ia32/codegen-ia32.cc	(revision 4462)
+++ src/ia32/codegen-ia32.cc	(working copy)
@@ -2773,11 +2773,7 @@
       // number comparison in the stub if it was inlined.
       CompareStub stub(cc, strict, nan_info, !inline_number_compare);
       Result answer = frame_->CallStub(&stub, &left_side, &right_side);
-      if (cc == equal) {
-        __ test(answer.reg(), Operand(answer.reg()));
-      } else {
-        __ cmp(answer.reg(), 0);
-      }
+      __ test(answer.reg(), Operand(answer.reg()));
       answer.Unuse();
       dest->Split(cc);
     } else {