Move vptr_{fieldno,basetype} out of main_type, and update everything accordingly.

Move vptr_{fieldno,basetype} out of main_type, and update everything accordingly.

Every type has to pay the price in memory usage for their presence.
The proper place for them is in the type_specific field which exists
for this purpose.

gdb/ChangeLog:

	* dwarf2read.c (process_structure_scope): Update setting of
	TYPE_VPTR_BASETYPE, TYPE_VPTR_FIELDNO.
	* gdbtypes.c (internal_type_vptr_fieldno): New function.
	(set_type_vptr_fieldno): New function.
	(internal_type_vptr_basetype): New function.
	(set_type_vptr_basetype): New function.
	(get_vptr_fieldno): Update setting of TYPE_VPTR_FIELDNO,
	TYPE_VPTR_BASETYPE.
	(allocate_cplus_struct_type): Initialize vptr_fieldno.
	(recursive_dump_type): Printing of vptr_fieldno, vptr_basetype ...
	(print_cplus_stuff): ... moved here.
	(copy_type_recursive): Don't copy TYPE_VPTR_BASETYPE.
	* gdbtypes.h (struct main_type): Members vptr_fieldno, vptr_basetype
	moved to ...
	(struct cplus_struct_type): ... here.  All uses updated.
	(TYPE_VPTR_FIELDNO, TYPE_VPTR_BASETYPE): Rewrite.
	(internal_type_vptr_fieldno, set_type_vptr_fieldno): Declare.
	(internal_type_vptr_basetype, set_type_vptr_basetype): Declare.
	* stabsread.c (read_tilde_fields): Update setting of
	TYPE_VPTR_FIELDNO, TYPE_VPTR_BASETYPE.

gdb/testsuite/ChangeLog:

	* gdb.base/maint.exp <maint print type argc>: Update expected output.