Use test(reg, imm) when the operand is a register on ia32

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/21521002

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

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16020 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ia32/assembler-ia32.cc

@@ -1227,6 +1227,10 @@ void Assembler::test_b(Register reg, const Operand& op) {
 
 
 void Assembler::test(const Operand& op, const Immediate& imm) {
+  if (op.is_reg_only()) {
+    test(op.reg(), imm);
+    return;
+  }
   EnsureSpace ensure_space(this);
   EMIT(0xF7);
   emit_operand(eax, op);