message: remove stream operator in Quic codec mock
  Summary:
  Apparently i can also inline to avoid multiple definition but it also
  seems this is no longer needed
diff: #include <quic/codec/QuicPacketBuilder.h>
  #include <quic/common/test/TestUtils.h>
  -namespace quic {
  -// Otherwise you won't be able to mock QuicPacketBuidlerBase::appendFrame()
  -std::ostream& operator<<(std::ostream& out, const QuicWriteFrame& /*rhs*/) {
  - return out;
  -}
  -} // namespace quic
  -
  namespace quic {
  namespace test {
  