TEST_MAPPING: test dependers of this crate am: b869c8b0a4 am: 1ccccdcb3e am: 15f9c57deb

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/structopt-derive/+/1488727

Change-Id: Ic2e05c26cf74f39d2854de9ffe5c4a4fc52cbe9c