Issue #2942900 by Mixologic, vaplas, jibran, dawehner, Lendude, martin107, alexpott, tedbow, tacituseu, tstoeckler, heddn: Convert JavascriptTestBase Tests to use DrupalSelenium2Driver

Revert "Issue #2942900 by Mixologic, vaplas, jibran, Lendude, martin107, alexpott, dawehner, tedbow, tacituseu, tstoeckler, heddn: Convert JavascriptTestBase Tests to use DrupalSelenium2Driver"

This reverts commit f55d9746.

Issue #2942900 by Mixologic, vaplas, jibran, Lendude, martin107, alexpott, dawehner, tedbow, tacituseu, tstoeckler, heddn: Convert JavascriptTestBase Tests to use DrupalSelenium2Driver

Revert "Issue #2808063 by vaplas, martin107, Chi, Wim Leers, catch, dawehner, alexpott: LibraryDiscoveryParser::buildByExtension() doesn't validate that extensions exist"

This reverts commit a68c44f4.

Issue #2808063 by vaplas, martin107, Chi, Wim Leers, catch, dawehner, alexpott: LibraryDiscoveryParser::buildByExtension() doesn't validate that extensions exist

Issue #2647916 by Lendude, Wim Leers, dawehner: Views ajax modals stop working in certain scenarios: due to JS settings caching, AJAX responses may set wrong ajaxPageState.libraries, causing problems for subsequent AJAX requests/responses