Like we do for GLSL; there's no reason to abort compilation here. Note
that this also avoids leaking "gen->buffer" and "gen->string_buffers" on
the error path.
With this we can finally disallow failure for the macOS CI script,
which is more valuable than checking DXC. Eventually DXC tests
will have to be fixed, though.
It's hard to pinpoint exactly what's going wrong with these
tests. They seem to be related to atomics and GPU timestamps,
both categories that are known to have problems on MoltenVK in a
way or another; those failures clearly depend on a few factors
like the MoltenVK version, the macOS version and whether we're in
a virtual machine or not, but the exact dependency on those factors
is hard to describe (for example, in general the paravirtualized
device offered inside virtual machines has a lot more problems than
real devices, but I've seen tests, fixed all other conditions,
working on the paravirtualized device and not on the real device).
The only thing all tests in this batch have in common is that I've
never seen them fail on a Sequoia system, thus I've settled for
using just that as the bug_if() condition. Ultimately, wasting a
lot of time to get to the bottom of each single test failure is
pointless, and being able to mark the CI job as not allowed to
fail gives better regression protection than investigating each
of those. Also, I routinely run the tests on a Sequoia system, so
if these tests get broken this is going to be noticed anyway.
