8970: fix: duplicate dependencies that have multiple DepKinds r=jonas-schievink a=jonas-schievink
Cargo collapses identical dependencies that are listed under `[dependencies]` and `[build-dependencies]` into a single `NodeDep`. We have to undo that by duplicating the dependency for each of its listed `DepKind`s.
Not doing that would incorrectly treat a dependency as `DepKind::Normal`, even though it is *also* meant to be a `DepKind::Build`.
Fixes https://github.com/rust-analyzer/rust-analyzer/pull/8812#issuecomment-847125395
bors r+
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>