Merge "Add instructions to generate java keystore" into main am: 31e9d3d1

Original change: https://android-review.googlesource.com/c/platform/build/+/3104279



Change-Id: I4d8f3b5ffb70c6eb707717884f9ebf440924ba61
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>