fix: Use MemoryManager::testInstance to check the MemoryManager initi…

…alization (#11926)

Summary:
Use `MemoryManager::testInstance` to check whether the MemoryManager
is initialized in `TraceReplayRunner.cpp` instead of `memory::memoryManager()`
as it uses `MemoryManager::instance`, which would throw if the MemoryManager
instance is null.

Pull Request resolved: #11926

Reviewed By: xiaoxmeng

Differential Revision: D67571450

Pulled By: tanjialiang

fbshipit-source-id: 1d0a91b27b124ff90ce3bbe38d7fe5d30319f5e1

velox/tool/trace/TraceReplayRunner.cpp

@@ -223,7 +223,7 @@ void TraceReplayRunner::init() {
   VELOX_USER_CHECK(!FLAGS_query_id.empty(), "--query_id must be provided");
   VELOX_USER_CHECK(!FLAGS_node_id.empty(), "--node_id must be provided");
 
-  if (memory::memoryManager() == nullptr) {
+  if (!memory::MemoryManager::testInstance()) {
     memory::initializeMemoryManager({});
   }
   filesystems::registerLocalFileSystem();