Shenandoah: TestAllocObjects.java test fail with -XX:+ShenandoahVerify

# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/home/zgu/ws/jdk/src/hotspot/share/gc/shenandoah/shenandoahVerifier.cpp:943), pid=6051, tid=6058
# Error: Verify Roots; Should not be forwarded

Referenced from:
  interior location: 0x00007f77202db418
  outside of Java heap
  0x00007f77202db418 is at entry_point+440 in (nmethod*)0x00007f77202db090

Object:
  0x00000000c01880c0 - klass 0x000000080008bbf8 jdk.internal.loader.ClassLoaders$AppClassLoader
    not allocated after mark start
        marked
        in collection set
  mark: marked(0x00000000fff80003)
  region: | 3|CS |BTE c0180000, c0200000, c0200000|TAMS c0200000|UWM c0200000|U 512K|T 479K|G 0B|S 33072B|L 33072B|CP 0

Forwardee:
  0x00000000fff80000 - klass 0x000000080008bbf8 jdk.internal.loader.ClassLoaders$AppClassLoader
        allocated after mark start
        marked
    not in collection set
  mark: mark(is_neutral hash=0x000000000c387f44 age=0)
  region: | 2047|R |BTE fff80000, 100000000, 100000000|TAMS fff80000|UWM 100000000|U 512K|T 0B|G 512K|S 0B|L 0B|CP 0


Bisecting points to pre JDK-8245961.