Fortran: Allow to nullify caf token when not in ultimate component. [PR101100]

gcc/fortran/ChangeLog:

	PR fortran/101100

	* trans-expr.cc (trans_caf_token_assign): Take caf-token from
	decl for non ultimate coarray components.

gcc/testsuite/ChangeLog:

	* gfortran.dg/coarray/proc_pointer_assign_1.f90: New test.