Fix a small bug in IoUringBackendTest

Summary: small bug

Differential Revision: D24080766

fbshipit-source-id: bb03739014023aa98b55859d433f88149529e5e7

folly/experimental/io/test/IoUringBackendTest.cpp

@@ -443,7 +443,7 @@ void testAsyncUDPRecvmsg(bool useRegisteredFds) {
   serverSocketVec.reserve(kNumSockets);
 
   std::vector<std::unique_ptr<folly::AsyncUDPSocket>> clientSocketVec;
-  serverSocketVec.reserve(kNumSockets);
+  clientSocketVec.reserve(kNumSockets);
 
   std::vector<std::unique_ptr<EventRecvmsgCallback>> cbVec;
   cbVec.reserve(kNumSockets);