Disable taskgroup test on freestanding; they're not supported

[ktoso]

rdar://109899236

Since none of the task group APIs are usable in freestanding, disable this freshly added test there as well:

-- Testing: 24 of 16230 tests, 10 workers --
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_cancelAll_only_specific_group.swift (1 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_asynciterator_semantics.swift (2 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_cancel_parent_affects_group.swift (3 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_cancel_then_spawn.swift (4 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_discarding_neverConsumingTasks.swift (5 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_discarding_dontLeak_class_error.swift (6 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_dontLeakTasks.swift (7 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_task_locals_prevent_illegal_use_taskgroup.swift (8 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_discarding_dontLeak.swift (9 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_next_not_invoked_cancelAll.swift (10 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_cancel_then_completions.swift (11 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/taskgroup_cancelAll_cancellationHandler.swift (12 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_next_not_invoked_without_cancelAll.swift (13 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_discarding.swift (14 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_next_on_pending.swift (15 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_is_empty.swift (16 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_throw_recover.swift (17 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/taskgroup_cancelAll_from_child.swift (18 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_task_locals_prevent_illegal_use_discarding_taskgroup.swift (19 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_throw_rethrow.swift (20 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_task_cancellation_taskGroup.swift (21 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_next_on_completed.swift (22 of 24)
UNSUPPORTED: Swift(freestanding-x86_64) :: Sanitizers/tsan/async_taskgroup_next.swift (23 of 24)
PASS: Swift(freestanding-x86_64) :: Concurrency/Runtime/async_taskgroup_is_asyncsequence.swift (24 of 24)

[ktoso]

@swift-ci please smoke test and merge

[ktoso]

@swift-ci please smoke test and merge