Issue #2367747 by Palashvijay4O, andypost, Alienpruts, Cottser, er.pushpinderrana, gaurav.pahuja, pfrenssen, rpayanm, vadim.hirbu: Remove usage of system_rebuild_theme_data()

Issue #2309737 by rpayanm, hussainweb, max-kuzomko, herom, millerbennett, ianthomas_uk, quietone, Sutharsan, sumitmadan, toddmbloom: Remove deprecated format_plural usage

Issue #1719648 by joachim, ttkaminski, kshama_deshmukh: ModuleInstaller::install() silently fails if a module isn't in the file system

Issue #2395395 by alexpott, effulgentsia, Gábor Hojtsy: TestBase lacks a config method to be used consistently in tests

Issue #2278017 by cilefen, bircher, effulgentsia: When a content entity type providing module is uninstalled, the entities are not fully deleted, leaving broken reference

Issue #2183983 by Gábor Hojtsy, vijaycs85, Berdir, Wim Leers, webflo, alexpott: Find hidden configuration schema issues

Issue #2347999 by Mile23, daffie, cs_shadow, cosmicdreams: DrupalUnitTestBase is deprecated, replace with KernelTestBase

Issue #2324055 by dawehner, cilefen, znerol: Split up the module manager into runtime information and extension information

Issue #697760 by sun: Replace getInfo() in tests with native phpDoc + annotations (following PHPUnit).

Issue #1906810 by dawehner, damiankloip, tstoeckler, kgoel, fubhy, jrglasgow, xjm, Gaelan, socketwench: Require type hints for automatic entity upcasting.

Revert "Issue #1906810 by dawehner, damiankloip, tstoeckler, kgoel, fubhy, jrglasgow, xjm, Gaelan, socketwench: Require type hints for automatic entity upcasting."

This reverts commit c9e73f7d.

Issue #1906810 by dawehner, damiankloip, tstoeckler, kgoel, fubhy, jrglasgow, xjm, Gaelan, socketwench: Require type hints for automatic entity upcasting.