tools: add log file param for api bench (#7713)

ref #7703

Signed-off-by: Cabinfever_B <cabinfeveroier@gmail.com>

Co-authored-by: ti-chi-bot[bot] <108142056+ti-chi-bot[bot]@users.noreply.github.com>

tools/pd-api-bench/config/config.go

@@ -54,6 +54,7 @@ func NewConfig(flagSet *flag.FlagSet) *Config {
 	fs := cfg.flagSet
 	fs.StringVar(&cfg.configFile, "config", "", "config file")
 	fs.StringVar(&cfg.PDAddr, "pd", "http://127.0.0.1:2379", "pd address")
+	fs.StringVar(&cfg.Log.File.Filename, "log-file", "", "log file path")
 	fs.StringVar(&cfg.StatusAddr, "status", "127.0.0.1:10081", "status address")
 	fs.Int64Var(&cfg.Client, "client", 1, "client number")
 	fs.StringVar(&cfg.CaPath, "cacert", "", "path of file that contains list of trusted SSL CAs")