Remove JSF stress test from integration test suite

Me and Tomas have agreed that org.jboss.weld.tests.stress.JsfStressTest should be removed from the integration test suite in both branches.

The test has no real value with regards to results it gives and we make no comparisons to previous runs. It delays test executions as it is the longest running test in the suite.
Last but not least, this test causes instability of our PR executor machines.

If we wish to execute stress testing, we might create a new Jenkins task in our perf suite although I don't see much benefit in this one in particular.