Problem/Motivation
Since we don't support PHP5 #3053363: Remove support for PHP 5 in Drupal 8.8 we no longer need to maintain \Drupal\Component\Utility\Crypt::hashEquals()
Proposed resolution
Deprecate the method for removal in Drupal 9.
Remaining tasks
Create change record
Add @deprecated to docblock
Add @trigger_error() to code
Remove all usages in core
Add legacy test to ensure we don;t break it for the remainder of Drupal 8 lifetime.
User interface changes
None
API changes
\Drupal\Component\Utility\Crypt::hashEquals() is deprecated
Data model changes
None
Release notes snippet
N/a