if #available + -disable-availability-checking seems to have been broken
since... TBD since when exactly. This means that these tests were not
executing at all (!), and when available became fixed, they actually
started executing and seems they hanged.
This fixes the tests however we should look into any other tests which
may have suffered from this and also since when these tests started
hanging -- it likely is a change in how isolation was inferred.
resolves rdar://154765383
This means that:
1. In test cases where minimal is the default (swift 5 without
-warn-concurrency), I added RUN lines for targeted, complete, and complete +
sns.
2. In test cases where complete is the default (swift 6, -warn-concurrency,
specified complete with -strict-concurrency), I added a send non-sendable run
line.
In each of these cases, I added additional expected-* lines as appropriate so
the tests can compile in each mode successfully.
Change the order of paths provided for `DYLD_LIBRARY_PATH` when running
tests for the back-deployed concurrency library, so they supersede the
ones in `/usr/lib/swift`. This way, we can test the back-deployed
concurrency library even on OS's that have the concurrency library in
them. It's not a complete test, because the standard library and
runtime will still vary, but can reproduce many failures more easily.
When using the back-deployed concurrency library, set the lit feature
`back_deploy_concurrency`. Update some tests that are unsupported with
back-deployment to check this.
Finally, add some logging when the concurrency runtime cannot be
tested at all, to help with debugging CI in the future.
