Fortran: Fix proc pointer as elemental arg handling

Fortran: Fix proc pointer as elemental arg handling

The vtab's _callback function calls the elemental 'cb'
  cb (var(:)%comp, comp_types_vtable._callback);
which gets called in a scalarization loop as 'var' might be a
nonscalar. Without the patch, that got translated as:
  D.1234 = &comp_types_vtable._callback
  ...
   cb (&(*D.4060)[S.3 + D.4071], &D.1234);
where 'D.1234' is function_type. With the patch, it remains a pointer;
i.e. D.1234 = comp... and 'cb (..., D.1234)', avoiding ME ICE.

Note: Fortran (F2018, C15100) requires that dummy arguments are
dummy data objects, which rules out dummy procs/proc-pointer dummies,
which is enforced in resolve_fl_procedure.
Thus, this change only affects the internally generated code.

gcc/fortran/ChangeLog:

        * trans-array.c (gfc_scalar_elemental_arg_saved_as_reference):
	Return true for attr.proc_pointer expressions.

gcc/testsuite/ChangeLog:

        * gfortran.dg/finalize_38.f90: Compile with -Ofast.