Fix rustc-guide build failure ignoring no-fail-fast.

This caused clippy not being built on Linux previously.

src/bootstrap/test.rs

@@ -1524,9 +1524,7 @@ impl Step for RustcGuide {
  fn run(self, builder: &Builder<'_>) {
  let src = builder.src.join("src/doc/rustc-guide");
  let mut rustbook_cmd = builder.tool_cmd(Tool::Rustbook);
- builder.run(rustbook_cmd
- .arg("linkcheck")
- .arg(&src));
+ try_run_quiet(builder, rustbook_cmd.arg("linkcheck").arg(&src));
  }
 }