Improvements to lmkd

- Don't show misleading messages, add the correct description for
  the reason of process killing
- Don't kill Launcher3 upgrade the score to perceptible (200)
- Limit the verbose logging

Test: tested on gobo
Bug: 64316273
Change-Id: Ic7c13853d939afe4f20cdaa5b488b6e1810f5ddf