8142952: Unified Logging framework does not allow multiple -Xlog: arguments.
Reviewed-by: brutisso, sla

8143229: Replace the develop level with develop macros in Unified Logging
Reviewed-by: brutisso, coleenp, dholmes, rprotacio

8046148: JEP 158: Unified JVM Logging
Reviewed-by: coleenp, sla