Revert "MULE-6889: Concurrent Modification Exception when using the Async Message Proccessor inside a foreach"

This reverts commit f80948519f58cd158aa5bcad048d4d642370e5d2.
Merge pull request #474 from mulesoft/MULE-6889

Revert "MULE-6889: Concurrent Modification Exception when using the Asyn...