This commit specifies Python_ROOT_DIR for each github action
since each Job may have a different version of Python and a
different path to the executable. By specifying Python_ROOT_DIR
each Job should get a valid path.

See if 5MW_OC4Semi_Linear will run faster when built using OpenBLAS

Trying to resolve issue with regression test failure when it
was previously passing

This reduces the number of parallel linearization regression tests in
GH actions in an attempt to keep the actions from failing

When using the Intel compiler, summing along a dimension of an array
creates a temporary copy which can be very large for 3D grid flow
fields. The Intel compiler tries to allocate this temporary array on the
stack, but it's too large and fails.