Implement strict comparison and native calls in flow graph compiler x64.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
===================================================================
--- runtime/vm/intermediate_language.h	(revision 5134)
+++ runtime/vm/intermediate_language.h	(working copy)
@@ -287,10 +287,22 @@
 
   DECLARE_COMPUTATION(NativeCall)
 
+  intptr_t token_index() const { return ast_node_.token_index(); }
+
   const String& native_name() const {
     return ast_node_.native_c_function_name();
   }
 
+  NativeFunction native_c_function() const {
+    return ast_node_.native_c_function();
+  }
+
+  intptr_t argument_count() const { return ast_node_.argument_count(); }
+
+  bool has_optional_parameters() const {
+    return ast_node_.has_optional_parameters();
+  }
+
  private:
   const NativeBodyNode& ast_node_;