Make OSS perf runner complain if ports needed are in use

Reviewed By: @JoelMarcey

Differential Revision: D1539467
Added the PHP port of several of Google's Octane suite of benchmarks.

Summary: I've ported the Octane benchmark harness (see: https://developers.google.com/octane/benchmark) and several of the Octane benchmarks to PHP. This is handy for comparing the performance of HHVM to other PHP implementations as well as to other dynamic language implementations like V8/JavaScriptCore.

Reviewed By: @ottoni

Differential Revision: D1534471