Testing profile no longer installs page cache and dynamic page cache

The testing profile, which is used to install the site under test in browser-based tests, no longer installs the page_cache and dynamic_page_cache modules. This means that any Functional or FunctionalJavascript tests that rely on those caching layers being in place will either need the module(s) added to the $modules property in the test class, or the module(s) installed in individual test method code.

Additionally, this means that tests that uninstalled either of those two modules no longer need to do so.