Fortran: Various CLASS + assumed-rank fixed [PR102541]

Starting point was PR102541, were a previous patch caused an invalid
e->ref access for class. When testing, it turned out that for
CLASS to CLASS the code was never executed - additionally, issues
appeared for optional and a bogus error for -fcheck=all. In particular:

There were a bunch of issues related to optional CLASS, can have the
'attr.dummy' set in CLASS_DATA (sym) - but sometimes also in 'sym'!?!
Additionally, gfc_variable_attr could return pointer = 1 for nonpointers
when the expr is no longer "var" but "var%_data".

	PR fortran/102541

gcc/fortran/ChangeLog:

	* check.c (gfc_check_present): Handle optional CLASS.
	* interface.c (gfc_compare_actual_formal): Likewise.
	* trans-array.c (gfc_trans_g77_array): Likewise.
	* trans-decl.c (gfc_build_dummy_array_decl): Likewise.
	* trans-types.c (gfc_sym_type): Likewise.
	* primary.c (gfc_variable_attr): Fixes for dummy and
	pointer when 'class%_data' is passed.
	* trans-expr.c (set_dtype_for_unallocated, gfc_conv_procedure_call):
	For assumed-rank dummy, fix setting rank for dealloc/notassoc actual
	and setting ubound to -1 for assumed-size actuals.

gcc/testsuite/ChangeLog:

	* gfortran.dg/assumed_rank_24.f90: New test.