[Polly][Isl] Use isl::set::tuple_dim, isl::map::domain_tuple_dim and isl::map::range_tuple_dim. NFC
This is part of an effort to reduce the differences between the custom C++ bindings used right now by polly in `lib/External/isl/include/isl/isl-noxceptions.h` and the official isl C++ interface.
Changes made:
- Use `isl::set::tuple_dim` instead of `isl::set::dim` and `isl::set::n_dim`
- Use `isl::map::domain_tuple_dim` instead of `isl::map::dim`
- Use `isl::map::range_tuple_dim` instead of `isl::map::dim`
- isl-noexceptions.h has been generated by this https://github.com/patacca/isl/commit/
45576e1b4260f91946e4cf819485f57bd2ed5490
Note that not all the usage of `isl::{set,map}::dim` where replaced
Reviewed By: Meinersbur
Differential Revision: https://reviews.llvm.org/D104994