Makefile: fix export log_level for gotest (#13197)
Makefile: fix export log_level for gotest (#13197)


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