make time func now related unit tests stable (#11412)
make time func now related unit tests stable (#11412)


kyle-wang/tidb,kyle-wang/tidb,c4pt0r/tidb,pingcap/tidb,ming-relax/tidb,EvilMcJerkface/tidb,qiuyesuifeng/tidb,XuHuaiyu/tidb,ngaut/tidb,ngaut/tidb,pingcap/tidb,ngaut/tidb,pingcap/tidb,c4pt0r/tidb,qiuyesuifeng/tidb,cosmtrek/tidb,kyle-wang/tidb,coocood/tidb,coocood/tidb,c4pt0r/tidb,Cofyc/tidb,ngaut/tidb,Cofyc/tidb,kyle-wang/tidb,pingcap/tidb,XuHuaiyu/tidb,kyle-wang/tidb,kyle-wang/tidb,c4pt0r/tidb,ming-relax/tidb,c4pt0r/tidb,EvilMcJerkface/tidb,pingcap/tidb,cosmtrek/tidb,ngaut/tidb,ngaut/tidb,c4pt0r/tidb,pingcap/tidb