[Ada] array and bounds in fat pointer can be a stub

[Ada] array and bounds in fat pointer can be a stub

This patch adds handling of the case when a fat pointer has the
P_ARRAY and/or P_BOUNDS fields defined as a stub.  In that case,
this stub needs to be resolved.

There are two issues:

  . First, making sure that the resolution takes place itself.
    That's the change to ada_check_typedef.

  . Make sure that the type returned after resolution is not itself
    a typedef.  This is the change to ada_check_typedef.

gdb/ChangeLog (Jerome Guitton, Joel Brobecker):

        * ada-lang.c (desc_bounds): Add handling of the case where
        the P_BOUNDS field is a pointer to a stub.
        (desc_data_target_type): Same for P_ARRAY field.
        (ada_check_typedef): Strip the typedef layers from the type
        found by ada_find_any_type.