[webapi] Add 2 TC for missing test point and delete unused files in weba...

Impacted Suites: webapi-webrtc-w3c-tests
Impacted TCs num: New 2, Update 0, Delete 2
Unit test platform: IVI
IVI test result summary: Pass 0, Fail 2, Blocked 0

Fail Reason:
The attribute setIdentityProvider and getIdentityAssertion are not support.

Remove TC check point repeat:
RTCPeerConnection_iceGatheringState.html >>
  RTCPeerConnection_basic.html
RTCPeerConnection_negotiationneeded_event.html >>
  blink/RTCPeerConnection-onnegotiationneeded.html