Merge "Add sdk/tools/BUILD.bazel to mark tools folder as a Bazel subpackage." am: a078142f86 am: 55ccd4e063 am: d9bd3c6e2b am: d98daa7c1c

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

Change-Id: I69184ba978a458d2ce9a6ef585bb81abc78a9385