Unrolled build for rust-lang#135256

Rollup merge of rust-lang#135256 - onur-ozkan:weird-mod-position, r=clubby789,jieyouxu

Move `mod cargo`  below the import statements

Just caught that during a [bootstrap reading-club](https://rust-lang.zulipchat.com/#narrow/channel/326414-t-infra.2Fbootstrap/topic/.5BBRC.5D.20How.20do.20Steps.20and.20Paths.20work.3F) session.

src/bootstrap/src/core/builder/mod.rs

@@ -1,5 +1,3 @@
-mod cargo;
-
 use std::any::{Any, type_name};
 use std::cell::{Cell, RefCell};
 use std::collections::BTreeSet;
@@ -25,6 +23,8 @@ use crate::utils::exec::{BootstrapCommand, command};
 use crate::utils::helpers::{self, LldThreads, add_dylib_path, exe, libdir, linker_args, t};
 use crate::{Build, Crate};
 
+mod cargo;
+
 #[cfg(test)]
 mod tests;