ddl: refactor ddl test for concurrency ddl (#33634)
ddl: refactor ddl test for concurrency ddl (#33634)

ref pingcap/tidb#33635
pingcap/tidb,ngaut/tidb,kyle-wang/tidb,kyle-wang/tidb,c4pt0r/tidb,ngaut/tidb,pingcap/tidb,c4pt0r/tidb,c4pt0r/tidb,c4pt0r/tidb,ngaut/tidb,kyle-wang/tidb,pingcap/tidb,pingcap/tidb,ngaut/tidb,pingcap/tidb,kyle-wang/tidb,c4pt0r/tidb,pingcap/tidb,c4pt0r/tidb,kyle-wang/tidb,ngaut/tidb,kyle-wang/tidb,ngaut/tidb