[webapi][XWALK-1330] Add 78 tests for Audio System API

- Add 78 TCs for audiosystem
- Audiosystem is not supported in Tizen IVI now.

Impacted TCs (designed): New 78, Update 0, Delete 0
Unit test Platform: Tizen IVI
IVI test result summary: Pass 0, Fail 0, Blocked 0
As to `support/unitcommon.js`, please don't change the file header!

This file was developed by Samsung, and all the files are the same copy in each Tizen Device API test suite. So, if you need to update it, please update all the files and go to Tizen TCT repo first.