Revert "lowmemorykiller: Use asynchronous compaction"

This reverts commit 1eedadff2a587a0185e4e5f8096acae20c80adb5.
Revert "lowmemorykiller: Compact memory when killing processes"

This reverts commit be515e5b9687a3823bfb5a8ffb159d78ffbe0588.