[SDK] BatchLogRecordProcessor is not calling thread instrumentation on shutdown

[marcalff]

In:

BatchLogRecordProcessor::DoBackgroundWork()

the following code is not invoked on shutdown:

#ifdef ENABLE_THREAD_INSTRUMENTATION_PREVIEW
  if (worker_thread_instrumentation_ != nullptr)
  {
    worker_thread_instrumentation_->OnEnd();
  }
#endif /* ENABLE_THREAD_INSTRUMENTATION_PREVIEW */

This is because of:

    if (synchronization_data_->is_shutdown.load() == true)
    {
      DrainQueue();
      return; <-- HERE
    }

The same code for traces uses a break instead of a return.