Merge changes from topic "default_psi_kill_mode"
* changes:
lmkd: Prevent killing foreground processes due to thrashing
lmkd: Add optional kill reason description into kill reports
lmkd: Enable new kill strategy, add and adjust required system properties
lmkd: Use aggregate zone watermarks as low memory threshold
lmkd: Introduce kill strategy based on zone watermarks, swap and thrashing
lmkd: Support variable polling intervals set by event handlers
lmkd: Change zoneinfo parsing to retrieve zone watermarks
lmkd: Change procfs read routine to handle files larger than 1 page in size