Issue #2563803 by borisson_, DietrichM: Remove deprecated functions from core/modules/system/tests/modules/module_test/module_test.module

Issue #2541344 by Wim Leers, borisson_, DietrichM, Xano, tim.plunkett, alvar0hurtad0, joshi.rohit100: BlockBase subclasses should merge their cache tags/contexts with the parent's (BlockBase's)