Add support for XMM registers in SSA code generation pipeline.

runtime/vm/assembler_ia32.h

Index: runtime/vm/assembler_ia32.h
diff --git a/runtime/vm/assembler_ia32.h b/runtime/vm/assembler_ia32.h
index 3bd3096cd76c4498979793703b53e70b80b7124a..c1e84723ed158719fcbb2108be6c8d532c9b9977 100644
--- a/runtime/vm/assembler_ia32.h
+++ b/runtime/vm/assembler_ia32.h
@@ -330,6 +330,8 @@ class Assembler : public ValueObject {
   void movsd(const Address& dst, XmmRegister src);
   void movsd(XmmRegister dst, XmmRegister src);
 
+  void movaps(XmmRegister dst, XmmRegister src);
+
   void addsd(XmmRegister dst, XmmRegister src);
   void addsd(XmmRegister dst, const Address& src);
   void subsd(XmmRegister dst, XmmRegister src);
@@ -581,6 +583,7 @@ class Assembler : public ValueObject {
   const Code::Comments& GetCodeComments() const;
 
   static const char* RegisterName(Register reg);
+  static const char* XmmRegisterName(XmmRegister reg);
 
  private:
   AssemblerBuffer buffer_;