gc: fix log format for gc worker (#7852)
gc: fix log format for gc worker (#7852)


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