planner/core: remove unstable test (#25138)
planner/core: remove unstable test (#25138)

Co-authored-by: Ti Chi Robot <040e6455cde1c91e876ec337e785ce913eacba35@tidb.io>
c4pt0r/tidb,c4pt0r/tidb,pingcap/tidb,kyle-wang/tidb,pingcap/tidb,ngaut/tidb,c4pt0r/tidb,coocood/tidb,kyle-wang/tidb,pingcap/tidb,c4pt0r/tidb,pingcap/tidb,kyle-wang/tidb,kyle-wang/tidb,coocood/tidb,ngaut/tidb,ngaut/tidb,c4pt0r/tidb,kyle-wang/tidb,pingcap/tidb,ngaut/tidb,kyle-wang/tidb,pingcap/tidb,ngaut/tidb,c4pt0r/tidb,ngaut/tidb