Remove invalid "test" attribute. am: d78a4dc913 am: 11541a49a8 am: 09db58e998 am: b6a1433786

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/linkme-impl/+/2780512

Change-Id: I72fc2c173a11b20c8bbe097a6158fa303c0c8833
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>