Problem/Motivation
When applying one or multiple sorts to config entity queries the results are not necessarily correct for a single sort, and are wrong if multiple sorts are applied becuase of the PHP-based sorting in:
In \Drupal\Core\Config\Entity\Query\Query::execute()
Proposed resolution
Correctly implement the sort comparator to return 0 if two values are equal and either implement multiple key sorts correctly or at least document the fact that they do not work.
Remaining tasks
test-only patch
fix patch
User interface changes
n/a
API changes
n/a
Data model changes
n/a