A64: Remove A64 special casing in ExternalCallbackScope

src/vm-state-inl.h

Index: src/vm-state-inl.h
diff --git a/src/vm-state-inl.h b/src/vm-state-inl.h
index 41690345cb987bceab7fad805732b480a61ec80e..5bee438b657577d2422ba1461eb91bf7647bd074 100644
--- a/src/vm-state-inl.h
+++ b/src/vm-state-inl.h
@@ -85,12 +85,7 @@ ExternalCallbackScope::ExternalCallbackScope(Isolate* isolate, Address callback)
       callback_(callback),
       previous_scope_(isolate->external_callback_scope()) {
 #ifdef USE_SIMULATOR
-#if V8_TARGET_ARCH_A64
-  scope_address_ = reinterpret_cast<Address>(Simulator::current(isolate)->sp());
-#else
-  int32_t sp = Simulator::current(isolate)->get_register(Simulator::sp);
-  scope_address_ = reinterpret_cast<Address>(static_cast<intptr_t>(sp));
-#endif
+  scope_address_ = Simulator::current(isolate)->get_sp();
 #endif
   isolate_->set_external_callback_scope(this);
 }