Upgrade lz4 to v1.9.4 am: 996c91caed am: d401c43615 am: 99b28c8705

Original change: https://android-review.googlesource.com/c/platform/external/lz4/+/2242764

Change-Id: If757d57a188bc9e3d3f427ab528c96407c500c71
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>