Fix MT unsafety in JetConstitFourMomTool
This fixes an issue with cluster retrieval which was reported in ATLASRECTS-6337. The problem turned out to be that the corresponding ReadHandleKeyArray in JetConstitFourMomTool was never declared as a property of the tool, meaning the dependency wasn't getting propagated to the scheduler. Hence this tool could sometimes be run before the clusters were available. This fixes the issue by using the auto-declaring constructors for this object (and the other properties as well for simplicity).