Reconsider naming rule of test suite directories

[Honry]

It's been discussed a while from #9895 (comment)

Existing naming rule for test suite directories is defined at http://web-platform-tests.org/introduction.html.

For W3C specs, these directories are typically named after the shortname of the spec (i.e. the name used for snapshot publications under /TR/)

For the purposes of auto-updating IDL it's simpler to pick a name based on the URL( https://w3c.github.io) we're getting the IDL from rather than where a snapshot might live.

But currently there are some cases of mismatched name between publication and ED, for some instances:

Latest published version: https://www.w3.org/TR/generic-sensor/
Editor's Draft: https://w3c.github.io/sensors/
Latest published version: https://www.w3.org/TR/mediacapture-streams/
Latest editor's draft: https://w3c.github.io/mediacapture-main/
Latest published version: https://www.w3.org/TR/appmanifest/
Latest editor's draft: https://w3c.github.io/manifest/
Latest published version: http://www.w3.org/TR/screen-capture/
Latest editor's draft: https://w3c.github.io/mediacapture-screen-share/
Latest Published Version: https://www.w3.org/TR/orientation-event/
Latest Editor's Draft: https://w3c.github.io/deviceorientation/

We need to think critically about whether the names make sense. Here I propose some options with concrete efforts will be required. PTAL.

1. Keep existing naming rule to use TR name, only effort is to fix code in auto-updating IDL tooling.
2. Keep existing naming rule to use TR name, leave the specname.idl mismatched with test suite name, no effort required.
3. Use the name after https://w3c.github.io/, much efforts for those mismatched cases, updating directory name and referenced link in corresponding spec documentations(spec, wiki, WG charter).
4. Coexistence, leave it to test suite owner to follow either TR name or ED name, leave it to auto-updating IDL tooling to determine the naming rule of specname.idl.
5. Other option, please comments.

cc @foolip, @jgraham, @gsnedders, @lukebjerring

[foolip]

I think that the minimum effort thing we could do is to document that when https://www.w3.org/TR/* is not equal to https://w3c.github.io/*/, then either is acceptable and we don't rename from one to the other unless there's a good reason.

@alvestrand, in the case of mediacapture-streams vs. mediacapture-main, do you expect that the discrepancy will remain forever, or that one of them will be renamed?