A64: Abstract simulation of runtime calls in a separate function.

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/203703002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20107 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/a64/simulator-a64.h

@@ -311,6 +311,7 @@ class Simulator : public DecoderVisitor {
   // Runtime call support.
   static void* RedirectExternalReference(void* external_function,
                                          ExternalReference::Type type);
+  void DoRuntimeCall(Instruction* instr);
 
   // Run the simulator.
   static const Instruction* kEndOfSimAddress;