message: compiletest can just propagate MIRI_SYSROOT from the outside
diff: @@ -87,22 +87,6 @@ fn miri_pass(path: &str, target: &str, opt: bool) {
  compiletest::run_tests(&config);
  }
  -/// Ensures that the `MIRI_SYSROOT` env var is set.
  -fn set_sysroot() {
  - if std::env::var("MIRI_SYSROOT").is_ok() {
  - // Nothing to do.
  - return;
  - }
  - let sysroot = std::process::Command::new("rustc")
  - .arg("--print")
  - .arg("sysroot")
  - .output()
  - .expect("rustc not found")
  - .stdout;
  - let sysroot = String::from_utf8(sysroot).expect("sysroot is not utf8");
  - std::env::set_var("MIRI_SYSROOT", sysroot.trim());
  -}
  -
  fn get_host() -> String {
  let rustc = rustc_test_suite().unwrap_or(PathBuf::from("rustc"));
  let rustc_version = std::process::Command::new(rustc)
  @@ -129,8 +113,6 @@ fn compile_fail_miri(opt: bool) {
  }
  fn test_runner(_tests: &[&()]) {
  - set_sysroot();
  -
  run_pass_miri(false);
  run_pass_miri(true);
  