Enable the profiler on the simulator

runtime/vm/simulator_arm64.cc

Index: runtime/vm/simulator_arm64.cc
diff --git a/runtime/vm/simulator_arm64.cc b/runtime/vm/simulator_arm64.cc
index 5f126e45cc9afc4cf7d294383a667173de77a80e..d284e1eeafe6b70bed2d6f2756e72a4aebba1119 100644
--- a/runtime/vm/simulator_arm64.cc
+++ b/runtime/vm/simulator_arm64.cc
@@ -630,6 +630,16 @@ class Redirection {
     return reinterpret_cast<Redirection*>(addr_of_redirection);
   }
 
+  static uword FunctionForRedirect(uword address_of_hlt) {
+    Redirection* current;
+    for (current = list_; current != NULL; current = current->next_) {
+      if (current->address_of_hlt_instruction() == address_of_hlt) {
+        return current->external_function_;
+      }
+    }
+    return 0;
+  }
+
  private:
   static const int32_t kRedirectInstruction = Instr::kRedirectInstruction;
   Redirection(uword external_function,
@@ -664,6 +674,11 @@ uword Simulator::RedirectExternalReference(uword function,
 }
 
 
+uword Simulator::FunctionForRedirect(uword redirect) {
+  return Redirection::FunctionForRedirect(redirect);
+}
+
+
 // Get the active Simulator for the current isolate.
 Simulator* Simulator::Current() {
   Simulator* simulator = Isolate::Current()->simulator();