[webapi] Add 73 exist TCs for webrtc

Impacted test suite: webapi-webrtc-w3c-tests
Impacted TCs num: New 73, Update 0, Delete 0
Unit test platform: IVI
IVI test result summary: Pass: 57, Fail 8, Block 8

Comment:
The TCs fail due to getConfiguration method is not support and the Identity API extends the RTCPeerConnection interface is not support.
The TCs block due to onidpvalidationerror event and onidentityresult event cannot be fired.