Fixes the idecoder in the case where:
  cm->error_resilient_mode == 0, and
  cm->frame_parallel_decoding_mode == 0, but
  new_fb->corrupted == 1.

The assert in debug_check_frame_counts fails to
take into account the case of a corrupt frame.

Change-Id: Idf318a68458cc88d65d6f3f408a10d8ffe87e43f