Test control flow instruction with optimizing compiler.

Add support for basic instructions to implement these tests.

Change-Id: I3870bf9301599043b3511522bb49dc6364c9b4c0
diff --git a/compiler/utils/x86/assembler_x86.h b/compiler/utils/x86/assembler_x86.h
index f8fc4c0..057c80a 100644
--- a/compiler/utils/x86/assembler_x86.h
+++ b/compiler/utils/x86/assembler_x86.h
@@ -354,6 +354,7 @@
   void orl(Register dst, Register src);
 
   void xorl(Register dst, Register src);
+  void xorl(Register dst, const Immediate& imm);
 
   void addl(Register dst, Register src);
   void addl(Register reg, const Immediate& imm);