Fortran: Fix detection of descriptor arrays in coarray [PR107635]

Look at the formal arguments generated type in the function declaration
to figure if an argument is a descriptor arrays.  Fix handling of class
types while splitting coarray expressions.

	PR fortran/107635

gcc/fortran/ChangeLog:

	* coarray.cc (fixup_comp_refs): For class types set correct
	component (class) type.
	(split_expr_at_caf_ref): Provide location.
	* trans-intrinsic.cc (conv_caf_send_to_remote): Look at
	generated formal argument and not declared one to detect
	descriptor arrays.
	(conv_caf_sendget): Same.