Parent Runner flag slows down the process execution on KIE Server

Commit introduced as a fix for RHPAM-2982 introduced a slowdown in performance on KIE Server. This is probably due to the fact that the line

txm.putResource(DROOLS_PARENT_RUNNER, TRUE);

accesses the transaction, which on KIE Server takes longer (3-6 ms increase in total time) than in the standalone engine, where the standalone narayana-jta is used.