Merge "Add sdk/tools/BUILD.bazel to mark tools folder as a Bazel subpackage." am: a078142f86 am: 55ccd4e063 am: d9bd3c6e2b

Original change: https://android-review.googlesource.com/c/platform/prebuilts/sdk/+/1677631

Change-Id: If2d6ee4119fb3d092ed31223ceb09eb9785f3c73