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 patch forces the main function to be protected behind MainActor
isolation. If no actor isolation is specified, the main function will
implicitly have MainActor isolation.
