Auto merge of #127680 - Kobzol:bootstrap-cmd-refactor-6, r=onur-ozkan

Bootstrap command refactoring: port remaining commands with access to `Build` (step 6)

Continuation of rust-lang/rust#127450.

This PR ports commands in bootstrap that can easily get access to `Build(er)` to `BootstrapCommand`. After this PR, everything that can access `Build(er)` should be using the new API.

Statistics of `bootstrap` code (ignoring `src/bin/<shims>`) after this PR:
```
7 usages of `Command::new`
69 usages of `command()` (new API)
 - out of that: 16 usages of `as_command_mut()` (new API, but accesses the inner command)
```

Tracking issue: rust-lang/rust#126819

r? `@onur-ozkan`

Author: bors