7133093: Improve system dictionary performanceSummary: implement one dictionary per ClassLoaderData for faster lookup and removal during class unloadingReviewed-by: iklam, acorn, jiangli
8067194: Restructure hotspot/agent/src to conform the modular source layoutSummary: Move sources under jdk.hotspot.agentReviewed-by: ihse, erikj, jbachorik