8026946: JvmtiEnv::SetBreakpoint and JvmtiEnv::ClearBreakpoint should use MethodHandle 8026948: JvmtiEnv::SetBreakpoint and JvmtiEnv::ClearBreakpoint might not work with anonymous classes Summary: Walk methods in breakpoints for marking on stack so they aren't deallocated by redefine classes. Use class_holder rather than class_loader to keep GC from reclaiming class owning the method. Reviewed-by: sspitsyn, ehelin, sla

project=jdk8