IC stub refilling currently requires a safepoint operation. When done right at the point where an IC cache is about to get patched to a transitional state using an IC stub, locks may already be held, causing a bunch of locking issues - especially for concurrent class unloading. Therefore, the IC stub refilling ought to be moved out so that IC cache cleaning and transitioning may be done without any safepoints, and the locks in the path ought to not perform safepoint checking.