Remove unnecessary QUIC_EXPORT directive.

PiperOrigin-RevId: 445159676

quiche/quic/test_tools/crypto_test_utils.cc

diff --git a/quiche/quic/test_tools/crypto_test_utils.cc b/quiche/quic/test_tools/crypto_test_utils.cc
index 3299b6c..3a1ef63 100644
--- a/quiche/quic/test_tools/crypto_test_utils.cc
+++ b/quiche/quic/test_tools/crypto_test_utils.cc
@@ -883,7 +883,7 @@
   }
 };
 
-class QUIC_EXPORT_PRIVATE TestProofVerifier : public ProofVerifier {
+class TestProofVerifier : public ProofVerifier {
  public:
   TestProofVerifier()
       : certificate_(std::move(