Generate first ARM assembler test and execute (simulate) it.

runtime/vm/simulator_mips.h

Index: runtime/vm/simulator_mips.h
===================================================================
--- runtime/vm/simulator_mips.h	(revision 18199)
+++ runtime/vm/simulator_mips.h	(working copy)
@@ -23,8 +23,22 @@
   Simulator();
   ~Simulator();
 
+  // The currently executing Simulator instance, which is associated to the
+  // current isolate
+  static Simulator* Current();
+
   // Call on program start.
   static void InitOnce();
+
+  // Dart generally calls into generated code with 5 parameters. This is a
+  // convenience function, which sets up the simulator state and grabs the
+  // result on return.
+  int64_t Call(int32_t entry,
+               int32_t parameter0,
+               int32_t parameter1,
+               int32_t parameter2,
+               int32_t parameter3,
+               int32_t parameter4);
 };
 
 }  // namespace dart