Disable retrieving crash reports from devices to make tree green.

Bug: 828951
No-Try: True
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I75de3b418241c9b97cda622cd9798f06e0e08f3d
Reviewed-on: https://chromium-review.googlesource.com/996240
Commit-Queue: Menglu Huang <huangml@chromium.org>
Reviewed-by: Sergey Berezin <sergeyberezin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548216}

ios/build/bots/scripts/test_runner.py

@@ -1023,7 +1023,8 @@ class DeviceTestRunner(TestRunner):
         logs_dir,
       ])
     except subprocess.CalledProcessError:
-      raise TestDataExtractionError()
+      # TODO(crbug.com/828951): Raise the exception when the bug is fixed.
+      print 'Warning: Failed to retrieve crash reports from the device.'
 
   def tear_down(self):
     """Performs cleanup actions which must occur after every test launch."""