added test running moldft with 2 mpi processes #1956

Job	Run time
macos-latest: clang++ Release Threads	17m 47s
macos-latest: clang++ Release OneTBB	1m 22s
macos-latest: clang++ Release PaRSEC	1m 43s
ubuntu-20.04: /usr/bin/g++-9 Release Threads	36m 10s
ubuntu-20.04: /usr/bin/g++-9 Release OneTBB	2m 20s
ubuntu-20.04: /usr/bin/g++-9 Release PaRSEC	2m 6s
macos-latest: clang++ Debug Threads	20m 32s
macos-latest: clang++ Debug OneTBB	1m 41s
macos-latest: clang++ Debug PaRSEC	1m 55s
ubuntu-20.04: /usr/bin/g++-9 Debug Threads	49m 17s
ubuntu-20.04: /usr/bin/g++-9 Debug OneTBB	1m 42s
ubuntu-20.04: /usr/bin/g++-9 Debug PaRSEC	1m 45s
	2h 18m 20s

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