Rollup merge of #160629 - moabo3li:priroda-bootstrap-ci, r=oli-obk

[Priroda] Add bootstrap test and check steps

The priroda crate lives under src/tools/miri/priroda and shares miri's sysroot and toolchain setup, so register a test step that mirrors the existing miri one and a check step alongside cargo-miri.

r? oli-obk

Author: JonathanBrouwer