Reduces flakiness of EndToEndTest.ConnectionMigrationClientPortChanged.

net/tools/quic/end_to_end_test.cc

Index: net/tools/quic/end_to_end_test.cc
diff --git a/net/tools/quic/end_to_end_test.cc b/net/tools/quic/end_to_end_test.cc
index ecf93c65355dcc04ca21627c86430a04143e46b3..e9e5f2a0ec22155ff330f8c6abcc905ed7721d54 100644
--- a/net/tools/quic/end_to_end_test.cc
+++ b/net/tools/quic/end_to_end_test.cc
@@ -1474,15 +1474,15 @@ TEST_P(EndToEndTest, ConnectionMigrationClientPortChanged) {
 
   // Store the client address which was used to send the first request.
   IPEndPoint old_address = client_->client()->GetLatestClientAddress();
-
-  // Stop listening and close the old FD.
-  QuicClientPeer::CleanUpUDPSocket(client_->client(),
-                                   client_->client()->GetLatestFD());
+  int old_fd = client_->client()->GetLatestFD();
 
   // Create a new socket before closing the old one, which will result in a new
   // ephemeral port.
   QuicClientPeer::CreateUDPSocketAndBind(client_->client());
 
+  // Stop listening and close the old FD.
+  QuicClientPeer::CleanUpUDPSocket(client_->client(), old_fd);
+
   // The packet writer needs to be updated to use the new FD.
   client_->client()->CreateQuicPacketWriter();