[Flang][OpenMP] Update semantics checks for 'teams' nesting (#126922)

This patch introduces a directive set for combined constructs where
`teams` is the last leaf. This is used in a couple places to simplify
checks, which is NFC, but it also replaces two incorrect uses of
`topTeamsSet`.

Before, these checks would incorrectly skip combined constructs where
`teams` was the last leaf construct when checking for allowed nested
constructs inside of a `teams` region. Similarly, it would also
incorrectly perform these checks whenever a compound `teams` construct
where `teams` was the first leaf construct was found.

0 files changed, 0 insertions, 0 deletions