message: IBM Backend: Default to multi_meas_enabled=false if missing
  Currently the JSON configuration for some IBM backends does not include
  multi_meas_enabled at all, causing a crash. Try to handle this, but be
  conservative and assume no multi_meas_enabled means
  multi_meas_enabled=false.
diff: @@ -258,7 +258,7 @@ void IBMAccelerator::initialize(const HeterogeneousMap &params) {
  chosenBackend = availableBackends[backend];
  xacc::info("Backend config:\n" + chosenBackend.dump());
  - multi_meas_enabled = chosenBackend["multi_meas_enabled"].get<bool>();
  + multi_meas_enabled = chosenBackend.value("multi_meas_enabled", false);
  defaults_response =
  get(IBM_API_URL,
  IBM_CREDENTIALS_PATH + "/devices/" + backend + "/defaults", {},
  