Merge "Don't hard-code number of tombstones." am: a4807cba22 am: d5076451dd am: d71722b665

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1592919

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I3f876be82debff768908ccd791b8402fe79147e2