message: sync: use HasReason() in double lock tests
  `HasReason()` is shorter than a lambda function.
diff: @@ -50,10 +50,8 @@ void TestDoubleLock(bool should_throw)
  MutexType m;
  ENTER_CRITICAL_SECTION(m);
  if (should_throw) {
  - BOOST_CHECK_EXCEPTION(
  - TestDoubleLock2(m), std::logic_error, [](const std::logic_error& e) {
  - return strcmp(e.what(), "double lock detected") == 0;
  - });
  + BOOST_CHECK_EXCEPTION(TestDoubleLock2(m), std::logic_error,
  + HasReason("double lock detected"));
  } else {
  BOOST_CHECK_NO_THROW(TestDoubleLock2(m));
  }
  