Fix by caching call metric recording stuff in async request

PR grpc#32106 caused msan errors in some tests while de-referencing the
server object where async calls are active after the server is
destroyed. Instead cache the ServerMetricRecorder pointer.

include/grpcpp/server_interface.h

@@ -186,6 +186,8 @@ class ServerInterface : public internal::CallHook {
     internal::Call call_wrapper_;
     internal::InterceptorBatchMethodsImpl interceptor_methods_;
     bool done_intercepting_;
+    bool call_metric_recording_enabled_;
+    experimental::ServerMetricRecorder* server_metric_recorder_;
   };
 
   /// RegisteredAsyncRequest is not part of the C++ API

src/cpp/server/server_cc.cc

@@ -155,6 +155,8 @@ ServerInterface::BaseAsyncRequest::BaseAsyncRequest(
   interceptor_methods_.SetCall(&call_wrapper_);
   interceptor_methods_.SetReverse();
   call_cq_->RegisterAvalanching();  // This op will trigger more ops
+  call_metric_recording_enabled_ = server_->call_metric_recording_enabled();
+  server_metric_recorder_ = server_->server_metric_recorder();
 }
 
 ServerInterface::BaseAsyncRequest::~BaseAsyncRequest() {
@@ -170,8 +172,8 @@ bool ServerInterface::BaseAsyncRequest::FinalizeResult(void** tag,
     }
     return true;
   }
-  context_->set_call(call_, server_->call_metric_recording_enabled(),
-                     server_->server_metric_recorder());
+  context_->set_call(call_, call_metric_recording_enabled_,
+                     server_metric_recorder_);
   context_->cq_ = call_cq_;
   if (call_wrapper_.call() == nullptr) {
     // Fill it since it is empty.