Fortran: Set hidden string length for pointer components [PR67740].

2023-10-11  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/67740
	* trans-expr.cc (gfc_trans_pointer_assignment): Set the hidden
	string length component for pointer assignment to character
	pointer components.

gcc/testsuite/
	PR fortran/67740
	* gfortran.dg/pr67740.f90: New test