Second codegen test passing on ARM (simulated).

runtime/vm/simulator_mips.h

Index: runtime/vm/simulator_mips.h
===================================================================
--- runtime/vm/simulator_mips.h	(revision 19404)
+++ runtime/vm/simulator_mips.h	(working copy)
@@ -16,6 +16,8 @@
 #error Do not include simulator_mips.h directly; use simulator.h.
 #endif
 
+#include "vm/constants_mips.h"
+
 namespace dart {
 
 class Simulator {
@@ -29,6 +31,10 @@
   // current isolate
   static Simulator* Current();
 
+  // Accessors for register state.
+  void set_register(Register reg, int32_t value);
+  int32_t get_register(Register reg) const;
+
   // Accessor to the internal simulator stack top.
   uword StackTop() const;