Merge tag 'android-9.0.0_r31' into lineage-16.0-android-9.0.0_r31

Android 9.0.0 Release 31 (PQ2A.190205.001)

* tag 'android-9.0.0_r31':
  DO NOT MERGE: lmkd: retune rate at which processes are killed
  init: increase thermal shutdown timeout to 3s
  Read memory stats from /proc/pid/stat file.
  lmkd: Implement pid purge command to clear old pids when zygote restarts
  lmkd: rate-limit and cleanup failed kill reports

Change-Id: Ia292a40ca57748f01bd6434d8e39bfca0abd2c35