LDEV-4400 Disable session ID change on demand
WildFly 10 changes session ID after log in by default. It prevent
session fixation attack.
TestHarness can not process it correctly. When calling /j_security_check
it gets session ID in SET-COOKIE header different to what Undertow
generates. Browsers seem to have no problem with it, but TestHarness
fails to set correct session ID. That is why session ID change needs to
be disabled when running TH.