Merge branch '11.x' of https://git.drupalcode.org/project/drupal into 3501727-try-to-simplify

* '11.x' of https://git.drupalcode.org/project/drupal:
  Issue #3497796 by mstrelan, shalini_jha, oily, nicxvan, smustgrave: Add return type to hook_file_download implementations
  Issue #3493911 by plopesc, catch, kristiaanvandeneynde, berdir, fabianx: Add a CachedPlaceholderStrategy to optimize render cache hits and reduce layout shift from big pipe
  Issue #3493813 by berdir, vladimiraus, catch, oily, e0ipso, pdureau, grimreaper: Drupal\Core\Theme\ComponentNegotiator::negotiate uses a lot of memory
  Issue #3496558 by alexpott, godotislate: Install entity definitions for all modules in batch install before simple config
  Issue #3502911 by tim.plunkett, nod_, catch: Compressed ajax_page_state['libraries'] can exist in both $request->request and $request->query simultaneously
  Issue #3504386 by plopesc, catch: Use a placeholder for the navigation toolbar
  Issue #3495881 by godotislate, bkosborne, catch, kushagra.goyal: Firefox retains form_build_id on form reloads, causing old form cache entry to be used and creating weird behavior for the Media Library widget
  Issue #3503870 by berdir: Assert all expected values of in PerformanceTestTrait::assertMetrics at once
  Issue #3501024 by mstrelan, smustgrave: Add array return to all hook_theme_suggestions_HOOK implementations
  Issue #3497405 by quietone, nod_: Fix DrupalPractice.Objects.GlobalFunction in tests
  Issue #3502629 by rkoller: Change the test-only pipeline service from with-chrome to with-selenium-chrome
  Issue #3441576 by plopesc, m4olivei, finnsky, catch, oily, gxleano, ckrina, aaronmchale, skaught: Add a new "Navigation user links" menu in favor of hardcoded links in NavigationUserBlock