Tests should follow what the specs say, and unless the specs define
the prefixed APIs [1] the right this is to assume the per-spec names
and to add historical.html tests asserting the absense of prefixed
APIs that have existed somewhere.

Based on web-confluence.appspot.com, navigator.vibrate was never
prefixed, but mozSrcObject is in Firefox. A test is added for
mozSrcObject, and the others APIs are already covered by existing
tests, or one of these:
https://github.com/w3c/web-platform-tests/pull/7507
https://github.com/w3c/web-platform-tests/pull/7508

[1] https://dom.spec.whatwg.org/#dom-element-webkitmatchesselector
    https://url.spec.whatwg.org/#url-class
    and others