Merge "Restore trimMemory behaviour from T" into udc-dev am: 90c9dbf7b9 am: 2a6a20b6da

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24733945

Change-Id: I7d58167b9ef230e1523f50873a590cf127705df0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>