Make it clearer _how_ to get a build... am: 53e18ffc28 am: 0430f70cf0 am: 054fa0dded

Original change: https://android-review.googlesource.com/c/platform/prebuilts/build-tools/+/2174343

Change-Id: I2fa45a42f712406316ef2a3a263e9d9294b96380
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>