hg: jdk9/hs-comp/hotspot: 8074553: Crash with assert(!is_unloaded()) failed: should not call follow on unloaded nmethod

[tobias.hartmann at oracle.com]

Changeset: 69648c4800f0
Author:    thartmann
Date:      2016-04-05 07:19 +0200
URL:       http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/69648c4800f0

8074553: Crash with assert(!is_unloaded()) failed: should not call follow on unloaded nmethod
Summary: Sweeper thread needs to override nmethods_do() to prevent G1 from unloading _scanned_nmethod.
Reviewed-by: kvn, mgerdin

! src/share/vm/runtime/thread.cpp
! src/share/vm/runtime/thread.hpp