sundials: update to 7.0.0
Remove some patches for issues that have been fixed upstream (differently).
Please, don't merge yet. The API changed in a backward-incompatible way and dependent packages need time to adapt for those changes.
As discussed in #20253, disable building with MPI for all environments.
The reason is that there is no actual MPI package in MSYS2. mingw-w64-msmpi only contains import libraries. A user would need to install MSMPI from Microsoft manually to be able to execute a program that links to SUNDIALS (even if the program that links to SUNDIALS doesn't actually use MPI).
Still left the logic for building with MPI intact. So, reverting this part should be easy.
Octave has been updated to version 9 in MSYS2. It should be compatible to SUNDIALS 7. The other dependent in MSYS2, mfem, is not compatible yet. See: https://github.com/mfem/mfem/issues/4169