skiplist: always return the entry after acquire succeeds in remove
skiplist: always return the entry after acquire succeeds in remove

Signed-off-by: Yilin Chen <9f6bed1fd69d0e15c5d9fbf33319f3d0f8cbc703@gmail.com>

crossbeam-rs/crossbeam,crossbeam-rs/crossbeam,crossbeam-rs/crossbeam,crossbeam-rs/crossbeam,aturon/crossbeam