Fortran: Fix gimplification error for pointer remapping in forall [PR107143]

Fortran: Fix gimplification error for pointer remapping in forall [PR107143]

Enhance dependency checking for data pointers to check for same derived
type and not only for a type being a derived type.  This prevent
generation of a descriptor for a function call, that is unsuitable in
forall's pointer assignment.

	PR fortran/107143

gcc/fortran/ChangeLog:

	* dependency.cc (check_data_pointer_types): Do not just compare
	for derived type, but for same derived type.

gcc/testsuite/ChangeLog:

	* gfortran.dg/forall_20.f90: New test.