fa73f8a4695d5bcbd054f4c68ee2a648c808afd2 ci: Use clang-12 and libcxx-12 for msan (MarcoFalke)
Pull request description:
Run the latest sanitizers to get the most implemented features
ACKs for top commit:
fanquake:
ACK fa73f8a4695d5bcbd054f4c68ee2a648c808afd2 - `--disable-hardening` matches what was just added to oss-fuzz.
Tree-SHA512: 2e533bb9273c97600176be2e41069a03f425aa586f9f32b8ed5f0c9844215a3a41e95a8edd58d044386e350807d6a1df09008a7da35428abd185a509ca71bd82