[Tooling] Avoid repeated hash lookups (NFC) (#131264)

Author: kazutakahirata

clang/lib/Tooling/RefactoringCallbacks.cpp

@@ -220,13 +220,14 @@ void ReplaceNodeWithTemplate::run(
     }
     }
   }
-  if (NodeMap.count(FromId) == 0) {
+  auto It = NodeMap.find(FromId);
+  if (It == NodeMap.end()) {
     llvm::errs() << "Node to be replaced " << FromId
                  << " not bound in query.\n";
     llvm::report_fatal_error("FromId node not bound in MatchResult");
   }
   auto Replacement =
-      tooling::Replacement(*Result.SourceManager, &NodeMap.at(FromId), ToText,
+      tooling::Replacement(*Result.SourceManager, &It->second, ToText,
                            Result.Context->getLangOpts());
   llvm::Error Err = Replace.add(Replacement);
   if (Err) {