[MCJIT] Replace JITEventListener::anchor (temporarily removed in r222861), and

move GDBRegistrationListener into ExecutionEngine to avoid layering violation.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222864 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ExecutionEngine/ExecutionEngine.cpp

@@ -48,6 +48,8 @@ ExecutionEngine *(*ExecutionEngine::MCJITCtor)(
 ExecutionEngine *(*ExecutionEngine::InterpCtor)(std::unique_ptr<Module> M,
                                                 std::string *ErrorStr) =nullptr;
 
+void JITEventListener::anchor() {}
+
 ExecutionEngine::ExecutionEngine(std::unique_ptr<Module> M)
   : EEState(*this),
     LazyFunctionCreator(nullptr) {