Minor Description
There is a sub-suite called XMLSuite that runs the XML tests,
but it does not currently run the XMLOptimizerTraceTest.
Since that test suite is a significant quite for exercising
Derby's XML support, it seems worth including that suite in
the XMLSuite.
This might require a bit of suite re-arrangement, to make sure
that we don't run XMLOptimizerTraceTest multiple times during larger suites.