Removed densify argument to packm_cntl_obj_create().

Details:
- Removed the "densify" bool_t argument to bli_packm_cntl_obj_create().
  This argument was inserted very early in BLIS's development, when it
  was anticipated that the developer may sometimes wish to pack a
  Hermitian, symmetric, or triangular matrix without making it dense.
  But as it turns out, if we are packing a matrix, we always want to
  make it dense in some way or another due to the fact that the micro-
  kernel only multiplies dense micro-panels. Thus, unless/until there
  is a real need for the feature, it seems reasonable to remove it from
  the packm_cntl API.
Updated old test drivers in 'test'.