Work around dotnet#7371

- Don't have a threading contention for stdout by only using stdout in the exception case; "starting..." adds minimal value, one can assume if the script is called it starts.
- sleep the main thread 2s before accessing stdout in case the exception case wants to happen

src/Microsoft.DotNet.Helix/Sdk/tools/azure-pipelines/reporter/run.py

@@ -1,6 +1,7 @@
 import os
 import re
 import sys
+import time
 import traceback
 import logging
 from queue import Queue
@@ -39,7 +40,6 @@ def __process(self, batch):
 
     def run(self):
         global workerFailed, workerFailedLock
-        self.__print("starting...")
         while True:
             try:
                 item = self.queue.get()
@@ -146,6 +146,7 @@ def main():
             worker.daemon = True
             worker.start()
 
+        time.sleep(2000)
         log.info("Beginning to read test results...")
 
         # In case the user puts the results in HELIX_WORKITEM_UPLOAD_ROOT for upload, check there too.