Extend request body tests with ARGS_POST case
Extend request body tests with ARGS_POST case

See the following issues for details:
https://github.com/SpiderLabs/ModSecurity/issues/1531
https://github.com/SpiderLabs/ModSecurity/pull/1886

SpiderLabs/ModSecurity-nginx,SpiderLabs/ModSecurity-nginx,SpiderLabs/ModSecurity-nginx