iframe test page should include the latest implementation

[rantonysamy]

in M64 - cross origin iframes going to be deprecated according to this document

https://sites.google.com/a/chromium.org/dev/Home/chromium-security/deprecating-permissions-in-cross-origin-iframes

So in the sample https://webrtc.github.io/test-pages/src/iframe-apprtc/ we need to have two test frames.

1. Current Implementation sample (<iframe width="90%" height="1200px" src="//appr.tc"></iframe>)
2. Future Request sample <iframe src="https://example.com" allow="geolocation; microphone; camera"></iframe>

So we can test two iframe formats.

[KaptenJansson]

Could you make a PR with these changes?

[rantonysamy]

Sure, On the way.