hg: jdk/jdk: 8202578: Revisit location for class unload events

[harold.seigel at oracle.com]

Changeset: 5303c6c05db6
Author:    hseigel
Date:      2018-08-28 10:10 -0400
URL:       http://hg.openjdk.java.net/jdk/jdk/rev/5303c6c05db6

8202578: Revisit location for class unload events
Summary: Use notify_unload_class() to post JFR class unload events instead of doing a separate traversal of the class loader data graph
Reviewed-by: lfoltan, coleenp, mgronlun, egahlin

! src/hotspot/share/classfile/classLoaderData.cpp
! src/hotspot/share/classfile/systemDictionary.cpp
! src/hotspot/share/oops/instanceKlass.cpp