Revert "Issue #2229145 by znerol, neclimdul, larowlan, joelpittet, almaudoh: Register symfony session components in the DIC and inject the session service into the request object"

This reverts commit b926f5d8.

Issue #2403105 by larowlan, idebr, mshaver: Add an empty text on "Add Custom Block" page when no custom block types are available

Issue #2421841 by neclimdul, tim.plunkett: Performance bug in ControllerResolver::getControllerFromDefinition()

Issue #2330181 by esod, ashutoshsngh, gaurav_varshney, ranjeet.paliwal, joshi.rohit100, er.pushpinderrana, oriol_e9g: Remove bootstrap.inc module_invoke()

Issue #2229145 by znerol, neclimdul, larowlan, joelpittet, almaudoh: Register symfony session components in the DIC and inject the session service into the request object

Issue #2408977 by geertvd: Fatal error: Cannot access protected property Drupal\block\Entity\Block::$id

Broke testing UI. Reverted.

This reverts commit dc5ef576.

Issue #2417647 by Wim Leers, effulgentsia: Add leading slash to paths within 'user-path:' URIs, to allow 'user-path:' URIs to point to the <none> route

Issue #2420751 by Wim Leers, mondrake, attiks: ImageEffectBase::transformDimensions() should have a sane default implementation

Issue #2421581 by amateescu: Node preview causes stale values to be kept indefinitely for exisiting nodes

Issue #2349677 by davidhernandez, Xen, emma.maria, runand, mortendk: Copy filter templates to Classy

Issue #2216271 by larowlan, dawehner, lokapujya, mariusz.slonina, Berdir: Regression: Shortcut links access is not checked

Issue #2421335 by alexpott: Using run-tests.sh with the --list option should not require a db (of any kind)

Issue #2349683 by davidhernandez, mortendk, Manuel Garcia, emma.maria, DickJohnson: Copy forum templates to Classy

Issue #2397729 by penyaskito, Gábor Hojtsy, plach, Kristen Pol: Content language settings cannot be configured for non-translatable types on the one page configuration form

Issue #1164784 by emma.maria, kattekrab, tadityar, DickJohnson, vermario, luco, Jeff Burnz, davidhernandez, David_Rothstein, webchick, Bojhan, LewisNyman, alexpott: “Triptych” term is not widely understood; add "Featured top" and "Featured bottom"

Issue #2421005 by tim.plunkett: Add \Drupal::hasContainer() instead of checking if \Drupal::getContainer() === NULL

This reverts commit 2c7e51c3.

Issue #2406103 by Berdir, alexpott: Remove hook_node_validate() and hook_node_submit() because they bypass the entity API

Issue #2396553 by nripeshtrivedi, fullerja: field.html.twig documentation on template suggestions is incorrect

Issue #2419005 by dawehner, alexpott: Aggregator: Uncaught PHP Exception Drupal\Component\Plugin\Exception\PluginNotFoundException: "The "FeedTitle" plugin does not exist."

Issue #1987832 by aspilicious, disasm, webflo, vijaycs85, adci_contributor, vks7056: Convert system_test callbacks to a new style controller

Issue #2394883 by Gábor Hojtsy, plach, jhodgdon: Language setup for entity and field based rendering in views is independent, confusing UI, lacking test coverage

Issue #2349071 by Upchuk, Cottser, pwolanin: EntityStorageException when trying to save a link over the maximum depth

Issue #2418209 by chintan.vyas, lucastockmann: Replace user facing strings that use drupal.org as example of an external url