Remove QUICHE_EXPORT to fix merge.

PiperOrigin-RevId: 500600580
diff --git a/quiche/quic/core/quic_connection_test.cc b/quiche/quic/core/quic_connection_test.cc
index e1e318b..2a5c9c1 100644
--- a/quiche/quic/core/quic_connection_test.cc
+++ b/quiche/quic/core/quic_connection_test.cc
@@ -2533,7 +2533,7 @@
 
 // A test implementation which migrates to server preferred address
 // on path validation suceeds. Otherwise, client cleans up alternative path.
-class QUICHE_EXPORT ServerPreferredAddressTestResultDelegate
+class ServerPreferredAddressTestResultDelegate
     : public QuicPathValidator::ResultDelegate {
  public:
   explicit ServerPreferredAddressTestResultDelegate(QuicConnection* connection)