Remap dynamic cast hint values to be consistent across ABIs.
* search.c (dynamic_cast_base_recurse): Remap generated value.
(get_dynamic_cast_base_type): Adjust documentation.
* tinfo.h (__user_type_info::dyncast): Likewise.
(__user_type_info::find_public_subobj): Remap BOFF meaning.
* tinfo.cc (__si_type_info::do_dyncast): Remap BOFF meaning.
(__class_type_info::do_dyncast): Likewise.
(__class_type_info::do_find_public_subobj): Likewise.
* tinfo2.cc (__dynamic_cast): Remap BOFF parameter.
From-SVN: r31538