bug: benchmark scripts and apisix command OSX compatibility for development

[qiukeren]

Issue description

Here are two uncompatible on OSX:

1. run.sh，sed sed -i "s/worker_processes .*/worker_processes $worker_cnt;/g" conf/nginx.confdoes not work on mac, it should be replaced with sed -i "" "s/worker_processes .*/worker_processes $worker_cnt;/g" conf/nginx.conf on MAC.
2. apisix when reload, os.execute return 3 values while linux return only 1.

what's more, I suggest change worker_processes \d+ to worker_processes .* in run.sh, because nginx.conf is usually set to worker_process = auto.

Environment

• apisix version (cmd: apisix version): 1.3
• OS: OSX