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.
This avoids us having to go down the less-efficient "salvage" path when
dealing with concurrency issues. It also fixes overloading behavior
when dealing with `@preconcurrency` and `@Sendable` functions,
such as in https://github.com/apple/swift/issues/59909.
