Merge "Wait for helper thread to finish in MonitorContendedEntered test" into main am: 92b03ef02b

Original change: https://android-review.googlesource.com/c/platform/external/apache-harmony/+/2969271

Change-Id: I8740f7fad3cd61a3e2f007648013735860895283
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>