Merge "Revert "Fix default mode for system alert window on low-RAM device."" into tm-dev am: 074f4aa6 am: f1980fd9 am: 07d05ed9 am: 01eb0cfd

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18365482



Change-Id: I94583d8f9ffdd55099a7de4f1bd247b2117e1a69
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>