libmemtrack: Use the lock to protect the initialization of am: 1dd94f0972 am: 0e94dc42f1 Original change: https://android-review.googlesource.com/c/platform/system/memory/libmemtrack/+/3255525 Change-Id: I35afa00a8a12e0287e2ef447e6175213f9a3deb6 Signed-off-by: Automerger Merge Worker <[email protected]>