Removed explicit uses of kokkos throughout code

kokkos getDefaultNode was being called unncessarily throughout the
code, but this is the default argument for any function calls
(like creating a TPetra map). Also trying to clean out any refs to
kokkos_classic in an effort to begin using kokkos_core.
Changed run_test script to check if the machine has openmpi or mpich

Uses the right execution call now automatically