[clang] [Clang][OpenMP] Handle check for pointer-based array sections (PR #157443)

[Amit Tiwari via cfe-commits]

amitamd7 wrote:

Yes indeed the `if (!OASE)` check is `FALSE` only once (when it is an single dimension array-section expression) and we would ideally want to get the `ElementType` to be deduced in that traversal itself for `OASE` case. I checked few cases where it hits off CAT, VAT while the one in `test_target_update_mapper_from_discontiguous.c` (and other mentioned tests in the ticket), it goes undetected. 

https://github.com/llvm/llvm-project/pull/157443