make provision to install version 6.4.0beta.2 (#8338)
make provision to install version 6.4.0beta.2 (#8338)

* make provision to install version 6.4.0beta.2

* drop flang.patch for the newer version per junghans

iulian787/spack,krafczyk/spack,tmerrick1/spack,LLNL/spack,mfherbst/spack,mfherbst/spack,mfherbst/spack,LLNL/spack,tmerrick1/spack,tmerrick1/spack,matthiasdiener/spack,LLNL/spack,matthiasdiener/spack,matthiasdiener/spack,tmerrick1/spack,iulian787/spack,iulian787/spack,krafczyk/spack,mfherbst/spack,iulian787/spack,LLNL/spack,matthiasdiener/spack,krafczyk/spack,iulian787/spack,LLNL/spack,krafczyk/spack,mfherbst/spack,tmerrick1/spack,krafczyk/spack,matthiasdiener/spack