Improve robustness of the testing
Improve robustness of the automated testing:
- Use MPI Exec from CMake find_package.
- Use PDI_PLUGIN_PATH: no more need for LD_LIBRARY_PATH trick or copy to the PDI default plugin folder.
- Ignore script path length in initialize json comparison.
- Detect non-MPI Catalyst build
Edited by Francois Mazen