message: Produce the exit codes that compiletest expects
diff: @@ -228,8 +228,12 @@ fn main() {
  }
  });
  +
  + let result = rustc_driver::run(move || {
  rustc_driver::run_compiler(&args, Box::new(MiriCompilerCalls {
  default: Box::new(RustcDefaultCalls),
  start_fn,
  - }), None, None);
  + }), None, None)
  + });
  + std::process::exit(result as i32);
  }
  