TableAccessibility and TableRowAccessibility miss autorelease

The TableAccessibility obj-c class should call [autorelease] on an object it allocates (see: [TableRowAccessibility alloc] and [ColumnAccessibility alloc]).

The TableRowAccessibility obj-c class should not call [retain] on an allocated object (see: [CellAccessibility alloc]).

"You own any object you create", see: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/mmRules.html