Fix passing -O1 to build from `cargo test`

Fix passing -O1 to build from `cargo test`

In 9e03087d6acbc876a5ad1c9b9d8746bf18d5ca86 we started setting
`opt-level` only on profile.test and not profile.dev. When that
commit was authored I tested only that rustc was being called with
opt-level set in its flags, not that the resulted run ran at the
speed I expected. It seems profile.test isn't applied properly to
dependencies or so, resulting in tests running much slower than
they do at profile.dev.opt-level=1.