proc-macro ABI breakage still affects the tests when a new stable version
releases. Ideally we'd still be able to run the tests on the rust-analyzer
repo without having to update the proc-macro ABI, but for now just to
unblock CI we will ignore them here, as they are still run in upstream.
CargoWorkspace's package list includes packages that are path
dependencies, even if those packages aren't actually members of the
cargo workspace. As a result, rust-analyzer's runnable finder, which
returns the target from the first workspace that has a matching package,
may select the wrong working directory, causing runnables to fail, e.g.,
```
error: package `root` cannot be tested because it requires dev-dependencies and is not a member of the workspace
```
To fix this, we filter out packages that aren't members of the workspace
when searching for targets.
Fixes#7764
Moving tests to `rust-analyzer` crate allows removing walkdir dependency
from `xtask`. It does seem more reasonable to keep tidy tests outside of
the "build system" and closer to other integration tests.
* Keep codegen adjacent to the relevant crates.
* Remove codgen deps from xtask, speeding-up from-source installation.
This regresses the release process a bit, as it now needs to run the
tests (and, by extension, compile the code).
