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:
- Stop using `isl::set::lex_le_set`. The official way to do this is to use `isl::map::lex_le_at`
- Removed `isl::set::lex_le_set` from `isl-noexceptions.h`
- `isl-noexceptions.h` has been generated by this 266fea1d3d
Reviewed By: Meinersbur
Differential Revision: https://reviews.llvm.org/D106269