[libc++] Fix the signature of std::rotl and std::rotr

- Changed parameters type in `std::rotr` and `std::rorl` functions from `unsigned int` to `int`.
- Implemented behaviour for negative parameter values.

Fixes #64544

Reviewed By: #libc, philnik

Spies: arichardson, philnik, libcxx-commits

Differential Revision: https://reviews.llvm.org/D157569