JBoss Server Migration Tool fails with WFLYEMB0021: Cannot start embedded process when migrating domain.xml file

Issue

JBoss Server Migration Tool fails with WFLYEMB0021: Cannot start embedded process when migrating domain.xml file. The $JBOSS_HOME/migration/logs/migration.log file shows:

    OPVDX001: Validation error in domain.xml --------------------------------
    |
    |  491: 
    |  492: <subsystem xmlns="urn:jboss:domain:transactions:1.5">
    |  493:     <core-environment path="var" relative-to="jboss.server.data.dir" node-identifier="${jboss.server.name}">
    |           ^^^^ The attribute 'path' is no longer supported
    |
    |  494:         <process-id>
    |  495:             <uuid></uuid>
    |  496:         </process-id>
    |
    | The primary underlying error message was:
    | > ParseError at [row,col]:[493,17]
    | > Message: WFLYTX0031: The attribute 'path' is no longer supported
    |
    |-------------------------------------------------------------------------------