Issue #2809305 by Upchuk, Pavan B S, Jo Fitzgerald, tim.plunkett, Berdir: Block Context assignment form element shows even if no options are available

(cherry picked from commit 55f13aac)

Revert "Issue #2822382 by voleger, pfrenssen, erozqba, RytoEX, borisson_, sidharthap, Jo Fitzgerald, shashikant_chauhan: Make every  property protected on classes extending BrowserTestBase and KernelTestBase"

This reverts commit 29d0958a.

Issue #2822382 by voleger, pfrenssen, erozqba, RytoEX, borisson_, sidharthap, Jo Fitzgerald, shashikant_chauhan: Make every  property protected on classes extending BrowserTestBase and KernelTestBase

(cherry picked from commit 69501f30)

SA-CORE-2017-001 by alexpott, benjy, Berdir, casey, cilefen, dawehner, Heine, klausi, larowlan, Mixologic, mlhess, pwolanin, samuel.mortenson, Wim Leers, xjm, YesCT

Issue #2854529 by alexpott, xjm, klausi, Chi, Mixologic: Fix Drupal.Scope.MethodScope - all methods should have scopes

Issue #2776975 by joelpittet, dawehner, tim.plunkett, xjm, pfrenssen: March 3, 2017: Convert core to array syntax coding standards for Drupal 8.3.x RC phase

Issue #2632434 by yongt9412, EclipseGc, ivanjaros, Berdir: Conditions are not limited by available contexts

Issue #2513534 by tim.plunkett, lokapujya, tedbow, LewisNyman, Manjit.Singh, alexpott, Maninders, Bojhan: Remove the 'disabled' region from Block UI

Issue #2537732 by Xano, tim.plunkett, gnuget, claudiu.cristea, drunken monkey, bojanz: PluginFormInterface must have access to the complete $form_state (introduce SubFormState for embedded forms)

Issue #2572777 by andypost, alexpott, attiks, andriyun: Fix 'Squiz.Strings.ConcatenationSpacing' coding standard

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2635238 by dsnopek, tim.plunkett: Contexts not mapped in time to use them in BlockInterface::access()

Issue #2574975 by alexpott, Cottser, izus: Allow (base-)themes to be excluded from the UI (e.g. blocks, Appearance)

Issue #2484645 by giancarlosotelo, Arla: Assigning context mapping: allow empty selection for optional contexts

Issue #2377757 by EclipseGc, tim.plunkett, Frando, Berdir, japerry, dsnopek, Wim Leers, Bojhan: Expose Block Context mapping in the UI

Issue #2545972 by alexpott, joelpittet, ericjenkins, stefan.r, Wim Leers, Cottser: Remove all code usages SafeMarkup::checkPlain() and rely more on Twig autoescaping

Issue #2512456 by tim.plunkett, legolasbo, MattA, dawehner, googletorp, darol100, Bojhan, webchick, andypost, ivanstegic, larowlan, lauriii, LewisNyman, tkoleary, rickvug, eliza411, lunk_rat, nickrosencrans, stpaultim, Mark LaCroix: Implement the new block layout design to emphasize the primary interaction of placing a block

Issue #2508547 by tim.plunkett, tannerjfco, neclimdul: Placing a block with same machine name of region causes region to disappear in admin UI

Issue #2382543 by rpayanm, ianthomas_uk: Remove usage of drupal_html_class() and drupal_clean_css_identifier()

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

Issue #2391245 by Gábor Hojtsy, Wim Leers: Resolve remaining misc issues with configuration schema fails

Issue #2263359 by jhodgdon: hook_help(): Top of page help sections can't link to help pages without a fatal error or checking for help module

Issue #2318755 by LinL, Devin Carlson, effulgentsia, catch: Block Module: Fix documentation that refers to enabling/disabling of modules

Issue #2350823 by lauriii, jhedstrom, Tim Bozeman, cilefen, davidhernandez, inqui, Cottser, xjm: Use the Classy theme in the Testing profile

Issue #1869476 by rteijeiro, LewisNyman, lauriii, Wim Leers, mdrummond, swentel, hosef, cbiggins, larowlan, sun, EclipseGc, Gábor Hojtsy: Convert global menus (primary links, secondary links) into blocks.

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

Issue #2277981 by tim.plunkett, EclipseGc, fago: Provide a service for handling context-aware plugins.

Issue #2088027 by tim.plunkett | YesCT: Just placed block keeps changed color even after saving the block layout page.

Issue #1956448 by benjy, tim.plunkett, ed.hollinghurst, YesCT: Use the block instance title on the block admin listing.

Issue #2043527 by tim.plunkett, vijaycs85, dawehner: Fixed Theme name is included in block machine name but should be stored as a key instead.

Issue #1987636 by kgoel, tim.plunkett, pdrake, vijaycs85, pguillard, jibran: Convert block_admin_demo() to a new style controller.

Issue #2097537 follow-up by olli: Fixed yet another random failure in Drupal\block\Tests\Views\DisplayBlockTest->testBlockCategory().

Issue #2074037 by Wim Leers, effulgentsia: Add drupalPostUrl() — drupalPost()/drupalPostAjax() are for forms only, D8 JS performs non-form HTTP requests.