Some tests in our test suite are unbelievably slow on GCC due to the
use of the always_inline attribute. See [1] for more details.
This patch introduces the GCC-ALWAYS_INLINE-FIXME lit feature to
disable tests that are plagued by that issue. At the same time, it
moves several existing tests from ad-hoc UNSUPPORTED: gcc-12 markup
to the new GCC-ALWAYS_INLINE-FIXME feature, and marks the slowest tests
reported by the CI as UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME.
[1]: https://discourse.llvm.org/t/rfc-stop-supporting-extern-instantiations-with-gcc/71277/1
Am I right to assume you changed all these cases in format/chrono? If that is the case I will abandon D135787.