Issue #2293419 by vijaycs85: Fixed Add config schema test to all configuration test in migration, fix bugs.
Issue #2284383 by tstoeckler, lokapujya: Fixed All assertSomething() functions should return a bool indicating pass or fail.
Issue #2286347 by jiv_e: Fixed install steps indenting for RTL languages.
Issue #1987424 by rteijeiro, oshelach, a-fro, JeroenT, joelpittet, Cottser, IshaDakota, InternetDevels, TommyK, Sutharsan, robmc, mark.labrecque, lokapujya, Gaelan, drupalninja99, Carolyn, jenlampton, longwave: Seven.theme - Convert theme_ functions to Twig.
Issue #1898452 by joelpittet, amitgoyal, gnuget, steinmb, thedavidmeister, jenlampton, zaphoyd, Cottser, robmc, disasm, azinoman | c4rl: Simpletest.module - Convert theme_simpletest_result_summary functions to Twig.
Issue #2266763 by ashepherd, kay_v, lauggh | scor: Add debug mode to FieldRdfaTestBase class.
Issue #936704 by Matt V., swentel, tim.plunkett, Jalandhar, jimi-o: Added Use confirm form before clearing log messages.
Issue #2188895 by lokapujya, seiplax | scor: Support RDFa output in entity reference field formatter.
Merge branch '8.x' into 1498662-comment-subject