ParallelOldGC: warning: chunk 0x0004c1ff is not empty: destination_count=1

The following warning appears intermittently when running
nightly tests with fastdebug builds and -XX:+UseParallelOldGC:

Java HotSpot(TM) Client VM warning: chunk 0x0004c1ff is not empty: destination_count=1
0 perm bot 0 top 1808 end 12287 new_top 1808
1 old bot 65536 top 302606 end 305663 new_top 302600
2 eden bot 305664 top 311808 end 311807 new_top 311731
3 from bot 311808 top 311808 end 312319 new_top 311808
4 to bot 319552 top 319552 end 325567 new_top 319552

See CR 6334748 for instructions on running one test that
occasionally triggers the warning.