SfcL2OfRendererDataListenerTest::invalidTableOffset() is broken

Specifically, the second test

// Table Offset must be greater than 1
change = createSfcOfRendererConfig(1, 100);
this.sfcL2OfRendererDataListener.onDataChanged(change);
verifySettersNotCalled();

passes in seemingly valid offset and causes the setters to be called. The test passes if it finishes before the thread has had a chance to run, but if the thread runs before the test finishes then the assertions fail (either those directly after this call or those after the following test).

https://git.opendaylight.org/gerrit/35343 provides the code necessary to verify the failure, but doesn't fix things.