The diagnostic for non-Sendable globa/static `let` properties was checking
for a Sendable conformance without considering `@preconcurrency`. Emit
this diagnostic via a `@preconcurrency`-sensitive path.
Fixes rdar://121889248.
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.
Asking for Sendable conformances on this path is going to lead to
a traversal of the stored properties of the type. If there is an
interface type computation ongoing, as is very likely the case, this
traversal can wind up causing a cycle when it forces the interface type
of a member once again.
Request only the non-structural conformances to break the cycle.
rdar://77189542
