They do not appear to have 15 in their repos anymore, and no traces can
be found of it in the history, as usual. They do have 11, 17, and 20, so
choose one randomly and hope it doesn't keep changing value.
Remove hard-coded framework test skip logic in skippable(), instead
annotate test.json with environments in which skip is expected.
(Mainly this is done with by testing the value of MESON_CI_JOBNAME now
set for linux jobs)
D lang compilers have an option -release (or similar) which turns off
asserts, contracts, and other runtime type checking. This patch wires
that up to the b_ndebug flag.
Fixes#7082