Issue #2258831 by sun | Wim Leers: Stream wrappers of test runner are not restored after test completion.

Issue #2167039 by likin, dawehner, Wim Leers, tstoeckler, vijaycs85: Regression: page cache tags broken, also: some routes incorrectly use _controller -> No page object in template variables -> Fatal in seven_preprocess_page().

Issue #2068471 by dawehner, Crell, tim.plunkett, jibran, fubhy, larowlan: Normalize Controller/View-listener behavior with a Page object.

Issue #1987816 by pdrake, disasm, ParisLiakos, pguillard, vijaycs85, dawehner: Convert system_batch_page() to a new style controller.