After the fix of SOLR-11268, inform() will get called for Runtime URPs. AtomicURPTest needs to be improved with "inform()" not getting explicitly called which caused the confusion.
Also SOLR-10734 still needs to be fixed, patch uploaded on the same jira while back.
AtomicUpdateProcessor complains missing UpdateLog
Multithreaded test/support for AtomicURP broken
Add an Atomic Update Processor