Fix PR 94578.

Fix PR 94578.

Our intrinsics do not handle spans on their return values (yet),
so this creates a temporary for subref array pointers.

2020-04-25  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/94578
	* trans-expr.c (arrayfunc_assign_needs_temporary): If the
	LHS is a subref pointer, we also need a temporary.

2020-04-25  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/94578
	* gfortran.dg/pointer_assign_14.f90: New test.
	* gfortran.dg/pointer_assign_15.f90: New test.