[UIMA-4013] reduce sync contention in fixed flow controller

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1625408 13f79535-47bb-0310-9956-ffa450edef68
[UIMA-4012] reduce sync contention.

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1625409 13f79535-47bb-0310-9956-ffa450edef68