Resolves: tdf#90138 don't try to save a marks OtherPos if it doesn't have one

Change-Id: I522a236015c91c0744b3018d3d4e4d6c65ea19ab

sw/source/core/undo/undobj.cxx

@@ -756,7 +756,7 @@ void SwUndoSaveCntnt::DelCntntIndex( const SwPosition& rMark,
                         if ( *pStt < rAnnotationEndPos && rAnnotationEndPos <= *pEnd )
                         {
                             bSavePos = true;
-                            bSaveOtherPos = true;
+                            bSaveOtherPos = pBkmk->IsExpanded(); //tdf#90138, only save the other pos if there is one
                         }
                     }
                 }