Merge "Create a simple README for bazel darwin prebuilts." am: 59048da6cd am: aa6513f98d am: 11b27bcbac am: 27e0e10943

Original change: https://android-review.googlesource.com/c/platform/prebuilts/bazel/darwin-x86_64/+/1622682

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I1aa0b66de55d48b7863a82e6a3d0777878456bbb