Reformat use declarations.

The previous commit updated `rustfmt.toml` appropriately. This commit is
the outcome of running `x fmt --all` with the new formatting options.

compiler/rustc_codegen_gcc/build_system/src/clone_gcc.rs

@@ -1,8 +1,8 @@
+use std::path::{Path, PathBuf};
+
 use crate::config::ConfigInfo;
 use crate::utils::{git_clone, run_command_with_output};
 
-use std::path::{Path, PathBuf};
-
 fn show_usage() {
     println!(
         r#"