Disable memory opt pass when DNNL is on (#21826)

* Disable memory opt pass when DNNL is on

* Refine comment above mem optimization pass enablement

test=develop

paddle/fluid/inference/api/analysis_config.cc

@@ -324,8 +324,8 @@ void AnalysisConfig::Update() {
   }
 
 #ifdef PADDLE_WITH_MKLDNN
-  // Do not optimize before quantization
-  if (enable_memory_optim_ && !use_mkldnn_quantizer_) {
+  // Do not optimize when mkldnn is on
+  if (enable_memory_optim_ && !use_mkldnn_) {
 #else
   if (enable_memory_optim_) {
 #endif