Re: [custom-elements-tests] Move pre-v1 custom elements tests to under "pre-v1" directory and update OWNER file (#2933)

Some of your paths are getting too long:
```
PATH LENGTH: /custom-elements/pre-v1/registering-custom-elements/unresolved-element-pseudoclass/unresolved-element-pseudoclass-css-test-registered-custom-tag-ref.html longer than maximum path length (153 > 150)

PATH LENGTH: /custom-elements/pre-v1/registering-custom-elements/unresolved-element-pseudoclass/unresolved-element-pseudoclass-css-test-registered-type-extension-ref.html longer than maximum path length (157 > 150)

PATH LENGTH: /custom-elements/pre-v1/registering-custom-elements/unresolved-element-pseudoclass/unresolved-element-pseudoclass-css-test-registered-type-extension.html longer than maximum path length (153 > 150)
```

View on GitHub: https://github.com/w3c/web-platform-tests/pull/2933#issuecomment-216124005

Received on Monday, 2 May 2016 07:38:13 UTC