Issue #1844956 by msonnabaum, beejeebus: Fixed Optimize date formatting performance.

core/includes/common.inc

core/lib/Drupal/Component/Datetime/DateTimePlus.php

core/lib/Drupal/Core/Datetime/Date.php

core/lib/Drupal/Core/Datetime/DrupalDateTime.php

...Drupal/Core/TypedData/Plugin/DataType/DateTimeIso8601.php

core/lib/Drupal/Core/TypedData/Plugin/DataType/Timestamp.php

...ules/comment/lib/Drupal/comment/CommentFormController.php

core/modules/datetime/datetime.module

.../Drupal/datetime/Plugin/field/field_type/DateTimeItem.php

...lib/Drupal/system/Tests/Datetime/DateTimePlusIntlTest.php

...ystem/lib/Drupal/system/Tests/TypedData/TypedDataTest.php

...views/lib/Drupal/views/Tests/Handler/ArgumentDateTest.php

...ests/Drupal/Tests/Component/Datetime/DateTimePlusTest.php