Remove ConfigFlags.Detector.SimulateXXX completely
After !41259 (merged) removed all usage of the Detector.Simulate ConfigFlags, it is now safe from them to be removed.
Doing so also makes the temporarily introduced SimulationTestHelpers module obsolete, so this is removed as well and replaced with sytnax added in !41441 (merged).
FYI @tadej, @dnoel, @bleban, @emoyse
Edited by John Derek Chapman