fdo#39944: Fix mapping for some a11y roles to ATK

In particular, EDIT_BAR, EMBEDDED_OBJECT and HYPER_LINK were being
mapped to custom roles when specific roles exist; fixed passing the
proper name to registerRole.

Besides, moved two roles that were in the section 'don't exist in ATK
yet' because that's not the case now.

Change-Id: I6818a0ac623f45053812b5c6dd5fc25c9abf4f65
(cherry picked from commit 7c37cd7bb26b91bda5e57d7bd0cecdbc9d1ebb22)
Reviewed-on: https://gerrit.libreoffice.org/10067
Reviewed-by: Norbert Thiebaud <nthiebaud@gmail.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>