protected Object invokeRaw(SpockExecutionContext context, Object target, MethodInfo method, Object... arguments) {
    try {
      return method.invoke(target, arguments);
    } catch (Throwable throwable) {
      supervisor.error(context.getErrorInfoCollector(), new ErrorInfo(method, throwable, ErrorContext.from(getSpecificationContext(context))));
      return null;
    }
  }
Executes a single Spec. Notifies its supervisor about overall execution
progress and every invocation of Spec code.
Supervisor also determines the error strategy.

@author Peter Niederwieser
spock-core/src/main/java/org/spockframework/runtime/PlatformSpecRunner.java