Switch from the abstract XAccessible UNO interface to the more concrete OAccessible for AccessibleGridControlBase::m_xParent and rename accordingly. Drop now no longer needed method calls and UNO queries to get the XAccessibleContext and XAccessibleComponent interfaces, because OAccessible directly implements those interfaces itself as well. Change-Id: I39e8453f087568c78c2f7de6634d87bde2717956 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/210633 Tested-by: Jenkins Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>