Testing workspace package with features expects the root package to have those features

Consider this project structure:

```
foo
├── bar
│   ├── Cargo.toml
│   └── src
│       └── lib.rs
├── Cargo.toml
└── src
    └── lib.rs
```

If I add a feature to `foo/bar/Cargo.toml` called `whatever` and I run

```
cargo test -p bar --features whatever
```

I get

```
error: Package `foo v0.1.0 (file://[...]/foo)` does not have these features: `whatever`
```
