addressing https://github.com/w3c/web-platform-tests/pull/271#discussion_r6414194
addressing https://github.com/w3c/web-platform-tests/pull/271#discussion_r6417932
addressing https://github.com/w3c/web-platform-tests/pull/271#discussion_r6417883
addressing https://github.com/w3c/web-platform-tests/pull/271#discussion_r6429632 (Moved from HTMLPreElement.width to HTMLOListElement.start)
addressing https://github.com/w3c/web-platform-tests/pull/271#discussion_r6450584 and https://github.com/w3c/web-platform-tests/pull/271#discussion_r6450617
addressing https://github.com/w3c/web-platform-tests/pull/271#discussion_r6450656