Remove Unused $block_storage variable from multiple file

The above patch looks fine.

1. +++ b/core/modules/system/system.post_update.php
   @@ -251,7 +251,7 @@ function system_post_update_entity_reference_autocomplete_match_limit(&$sandbox
   -    foreach ($display->getComponents() as $field_name => $component) {
   +    foreach ($display->getComponents() as $component) {
   

   As per this is not an unused variable. See #3105981-11: Remove unused variable from view.module for ideas on further work about unused variables.

2. +++ b/core/modules/system/system.post_update.php
   --- a/core/modules/system/tests/src/Functional/Update/PageTitleConvertedIntoBlockUpdateTest.php
   +++ b/core/modules/system/tests/src/Functional/Update/PageTitleConvertedIntoBlockUpdateTest.php
   
   +++ b/core/modules/system/tests/src/Functional/Update/PageTitleConvertedIntoBlockUpdateTest.php
   --- a/core/modules/system/tests/src/Functional/Update/SevenSecondaryLocalTasksConvertedIntoBlockUpdateTest.php
   +++ b/core/modules/system/tests/src/Functional/Update/SevenSecondaryLocalTasksConvertedIntoBlockUpdateTest.php
   
   +++ b/core/modules/system/tests/src/Functional/Update/SevenSecondaryLocalTasksConvertedIntoBlockUpdateTest.php
   --- a/core/modules/system/tests/src/Functional/Update/SiteBrandingConvertedIntoBlockUpdateTest.php
   +++ b/core/modules/system/tests/src/Functional/Update/SiteBrandingConvertedIntoBlockUpdateTest.php
   

   These are all being removed as part of #3087644: Remove Drupal 8 updates up to and including 88**

The above two points mean this issue is closed - won't fix - but @Hardik_Patel_12 note the advice in #3105981-11: Remove unused variable from view.module if you want to work on removing unused variables from core.