Fortran: diagnostics for actual arguments to pointer dummy arguments [PR94104]

Error message improvement.  In Fortran 2008 actual procedure arguments
associated with a pointer, intent(in) attribute, dummy argument
can also have the target attribute, not just pointer.

gcc/fortran/ChangeLog:

	PR fortran/94104
	* interface.cc (gfc_compare_actual_formal): Improve error message
	dependent on Fortran standard level.

gcc/testsuite/ChangeLog:

	PR fortran/94104
	* gfortran.dg/parens_2.f90: Adjust to improved error message.
	* gfortran.dg/PR94104a.f90: New test.
	* gfortran.dg/PR94104b.f90: New test.