Auto merge of #49321 - ishitatsuyuki:compile-pass, r=alexcrichton

Introduce compile-pass

r? @alexcrichton

The plan is to move things that cannot fail (no assert, unwrap, etc) out so we don't have to run them, and in the long term we can also stop running LLVM for them.

Out of 3215 tests...

```
Language            Files        Lines         Code     Comments       Blanks
Rust                 3215       119254        64688        35135        19431
```

16% of them has an empty main (which is already moved in this PR).

```
grep -rnPzl 'fn main\(\)\s*{\s*}' | xargs rg --files-without-match cfg | wc -l
547
```

And only 50% of the tests contains assertions:

```
rg -e assert -e unwrap -e expect -e panic -l | wc -l
1600
```

The remainder is likely able to get moved, but they need check by a human so I didn't touch them in PR.

cc @rust-lang/compiler

* [ ] Update documentation