br: ignore mock directory when gcov in br (#30586)
br: ignore mock directory when gcov in br (#30586)

 
ngaut/tidb,ngaut/tidb,c4pt0r/tidb,c4pt0r/tidb,pingcap/tidb,kyle-wang/tidb,kyle-wang/tidb,c4pt0r/tidb,ngaut/tidb,c4pt0r/tidb,pingcap/tidb,c4pt0r/tidb,kyle-wang/tidb,kyle-wang/tidb,c4pt0r/tidb,pingcap/tidb,ngaut/tidb,pingcap/tidb,kyle-wang/tidb,kyle-wang/tidb,pingcap/tidb,pingcap/tidb,ngaut/tidb,ngaut/tidb