Revert "Use memset/madv_free instead of dontneed in foreground state."

This reverts commit 91fb2718a95d03b366fa9eab514f4d751647dd80.

Bug: 287846662

Reason for revert: b/287846662

Change-Id: I06a5704d169b1fed7e69fe9f94edd2be463528b9
14 files changed