quiche make check build failure

[bneradt]

I added a quiche branch build job for 10-Dev. It looks like make check fails compilation: https://ci.trafficserver.apache.org/view/10-Dev/job/10-Dev/job/quiche/2/

In file included from ./test/test_QPACK.cc:31:
./../../iocore/net/quic/Mock.h:656:3: error: 'virtual QUICRTTProvider* MockQUICContext::rtt_provider() const' marked 'override', but does not override
  656 |   rtt_provider() const override
      |   ^~~~~~~~~~~~
./../../iocore/net/quic/Mock.h:662:3: error: 'virtual QUICPacketProtectionKeyInfo* MockQUICContext::key_info() const' marked 'override', but does not override
  662 |   key_info() const override
      |   ^~~~~~~~
./../../iocore/net/quic/Mock.h:668:3: error: 'virtual QUICLDConfig& MockQUICContext::ld_config() const' marked 'override', but does not override
  668 |   ld_config() const override
      |   ^~~~~~~~~
./../../iocore/net/quic/Mock.h:674:3: error: 'virtual QUICCCConfig& MockQUICContext::cc_config() const' marked 'override', but does not override
  674 |   cc_config() const override
      |   ^~~~~~~~~
./../../iocore/net/quic/Mock.h:680:3: error: 'virtual QUICPathManager* MockQUICContext::path_manager() const' marked 'override', but does not override
  680 |   path_manager() const override
      |   ^~~~~~~~~~~~
make[3]: *** [Makefile:1143: test/test_qpack-test_QPACK.o] Error 1

Steps for Reproduction

• docker image: ci.trafficserver.apache.org/ats/rockylinux:8
• Branch: 10-Dev
• configure: /configure --enable-experimental-plugins --enable-example-plugins --with-quiche=/opt/quiche --prefix=/tmp/ats --enable-werror --enable-debug
• make -j4 && make install && make -j4 check

[bneradt]

Closing because @maskit fixed this via #9304. (Looks like github doesn't automatically close issues via non-master PRs?)