Make both Error and CodingKey conform to ConcurrentValue, so that
thrown errors always conform to ConcurrentValue. Downgrade (to
warnings) and ConcurrentValue-related diagnostics that are triggered
by this change in existing Error and CodingKey-conforming types to
reduce the impact on source compatibility.
This is only relevant for assert builds of the library.
Fixes an undefined symbol error if an executable, compiled with an assert build of the stdlib, is back deployed on a platform which does not support lazy symbol binding.
rdar://problem/71201102
The standard library on non-Intel targets get compared to the baseline
from the Intel targets which is not guaranteed to be identical. Mark
the checks as expected failures on non-x86_64 targets. Although this is
entirely unsatisfying, it allows progress in the short term.
