Test scalapack/*: restrict all scalapack tests to less than 10 mpi ranks

Test scalapack/*: restrict all scalapack tests to less than 10 mpi ranks

Let us restrict the maximal concurrency of scalapack tests to less than
10 MPI ranks:

 - The purpose of these tests is to test our interfaces to scalapack and
   not whether scalapack functions properly for high(er) MPI
   concurrency. As such testing a few variants with a low number of MPI
   ranks is enough.

 - This cuts down the number of tests in our testsuite that have a
   concurrency of 10 or more from around 225 to around 190.

   The issue with these tests is the fact that we have to block off
   parallel slots in the ctest run equal to the number of MPI ranks.
   Meaning the more tests we have that have a high number of MPI ranks
   the less optimal the scheduling in ctest.