Integrity checker should fix invalid references from field configuration to field configuration scheme

Summary

From time to time, Jira's fieldlayoutschemeentity table has abandoned references from a field configuration to a field configuration scheme.

Steps to Reproduce

Apart from manually deleting field configuration schemes from the database, it's not clear how this issue can be reproduced.

Expected Results

The integrity checker should remove missing references.

Actual Results

The integrity checker should remove missing references from the fieldlayoutschemeentity table.
The following error is logged:

com.atlassian.cache.CacheException: com.atlassian.jira.exception.DataAccessException: No FieldLayoutScheme found for id 22601

Workaround

Delete the missing references:

DELETE FROM fieldlayoutschemeentity WHERE scheme NOT IN (SELECT id FROM fieldlayoutscheme);