fix memory_reuse_pass memory_size calculation error, test=develop (#19020)

paddle/fluid/framework/ir/memory_optimize_pass/memory_reuse_pass.cc

@@ -100,8 +100,10 @@ VarDesc *MemoryReusePass::GetVarDesc(const details::VarHandle &var) const {
 int64_t MemoryReusePass::GetMemorySize(const details::VarHandle &var) const {
   auto *var_desc = GetVarDesc(var);
   auto shapes = var_desc->GetShape();
+  auto sizeof_dtype = static_cast<int64_t>(SizeOfType(var_desc->GetDataType()));
   return std::accumulate(shapes.begin(), shapes.end(), static_cast<int64_t>(1),
-                         std::multiplies<int64_t>());
+                         std::multiplies<int64_t>()) *
+         sizeof_dtype;
 }
 
 void MemoryReusePass::CollectShareTensorBufferOpHandles() const {