Mitigate google/oss-fuzz#12519

It's caused by this exception
https://pantheon.corp.google.com/errors/detail/CNXrgouhptTW3QE;filter=%5B%22%5C%22Corpus%20pruning%20failed:%20%5BErrno%202%5D%20No%20such%20file%20or%20directory%5C%22%22%5D;locations=global?e=-13802955&mods=logs_tg_prod&project=google.com:clusterfuzz

Author: jonathanmetzman

src/clusterfuzz/_internal/bot/tasks/utasks/corpus_pruning_task.py

@@ -744,8 +744,8 @@ def _upload_corpus_crashes_zip(result: CorpusPruningResult,
 
 def _process_corpus_crashes(output: uworker_msg_pb2.Output):  # pylint: disable=no-member
   """Process crashes found in the corpus."""
-  if not output.corpus_pruning_task_output.crashes:
-    return
+  # if not output.corpus_pruning_task_output.crashes:
+  return
 
   corpus_pruning_output = output.corpus_pruning_task_output
   crash_revision = corpus_pruning_output.crash_revision