message: clean up an unused pair of parentheses
  While this might seem like too trivial of a stylistic nitpick to deserve
  its own commit, this is needed to unblock rust-lang/rust#46980 (which makes
  the unused-parens lint look at function arguments).
diff: @@ -120,7 +120,7 @@ fn run_unit_tests(options: &TestOptions,
  let (kind, test, e) = errors.pop().unwrap();
  Ok((Test::UnitTest(kind, test), vec![e]))
  } else {
  - Ok((Test::Multiple, errors.into_iter().map((|(_, _, e)| e)).collect()))
  + Ok((Test::Multiple, errors.into_iter().map(|(_, _, e)| e).collect()))
  }
  }
  