Extends the work started in #165714 by supporting team reductions. Similar to what was done in #165714, this PR introduces proper allocations, loads, and stores for by-ref reductions in teams-related callbacks: * `_omp_reduction_list_to_global_copy_func`, * `_omp_reduction_list_to_global_reduce_func`, * `_omp_reduction_global_to_list_copy_func`, and * `_omp_reduction_global_to_list_reduce_func`.