infoschema: improve test stability in other timezones (#20704)
infoschema: improve test stability in other timezones (#20704)

 
pingcap/tidb,ngaut/tidb,EvilMcJerkface/tidb,c4pt0r/tidb,c4pt0r/tidb,kyle-wang/tidb,coocood/tidb,kyle-wang/tidb,pingcap/tidb,kyle-wang/tidb,kyle-wang/tidb,XuHuaiyu/tidb,pingcap/tidb,ngaut/tidb,coocood/tidb,EvilMcJerkface/tidb,pingcap/tidb,kyle-wang/tidb,c4pt0r/tidb,ngaut/tidb,c4pt0r/tidb,ngaut/tidb,XuHuaiyu/tidb,pingcap/tidb,c4pt0r/tidb,ngaut/tidb,c4pt0r/tidb,pingcap/tidb,ngaut/tidb,kyle-wang/tidb