Update web-platform-tests

[annevk]

As noted by @marcoscaceres in web-platform-tests/wpt#30168 there's quite a few tests around that are not testing Permissions Policy, but are testing Feature Policy which is now obsolete. At a high level I think there's these two things to be done:

• Rename existing tests and update syntax as appropriate.
  • webxr: Feature-Policy is now Permissions-Policy web-platform-tests/wpt#37104
  • webvr: Feature-Policy is now Permissions-Policy web-platform-tests/wpt#37105
  • ...
• Add a couple of negative tests to ensure the old name and syntax are no longer supported.