[mlir][acc] Improve acc.loop support as a container (#137887)

Dialects which have their own loop representation not representable with
numeric bounds + steps cannot be represented cleanly with acc.loop. In
such a case, we permit the dialects representation with acc.loop merely
encompasing its loop representation. This limitation became obvious when
looking at range / random iterator C++ loops.

The API of acc.loop was updated to test for this differentiation.
Additionally, the verifier was updated to check for consistent bounds
and whether inner-loops are contained when it works as a container.

0 files changed, 0 insertions, 0 deletions