Merge "Revert^2 "OpenJDK 11: Merging in java.lang.ref.Cleaner"" am: 9000f9efcb

Original change: https://android-review.googlesource.com/c/platform/libcore/+/1914768

Change-Id: I631d00e3a3113a3a153817327d0d5b72d2a9e06f