Rework the log scanning code in the tree conflict resolver, so that it would use a single RA session to perform the additional requests (by reparenting it, instead of opening a new session every time).
* subversion/libsvn_client/conflicts.c (find_deleted_rev_baton): Add new 'extra_ra_session' field. (find_revision_for_suspected_deletion): Initialize the extra session by duplicating the existing session. (check_move_ancestry): Accept an RA session, instead of a client context. Reparent the session if needed, and use it to perform requests. (find_moves_in_revision): Accept an RA session, instead of a client context. (find_deleted_rev): Pass the extra RA session.