+ ./mach filter-intermittents wpt-jsonsummary.log --log-intermittents intermittents.log --log-filteredsummary filtered-wpt-errorsummary.log --tracker-api default --reporter-api default
Error running mach:
    ['filter-intermittents', 'wpt-jsonsummary.log', '--log-intermittents', 'intermittents.log', '--log-filteredsummary', 'filtered-wpt-errorsummary.log', '--tracker-api', 'default', '--reporter-api', 'default']
The error occurred in code that was called by the mach command. This is either
a bug in the called code itself or in the way that mach is calling it.
You should consider filing a bug for this issue.
If filing a bug, please include the full output of mach, including this error
message.
The details of the failure are as follows:
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 57: ordinal not in range(128)
  File "/Users/worker/tasks/task_1575999096/repo/python/servo/testing_commands.py", line 580, in filter_intermittents
    format(actual_failures, description)
  File "/Users/worker/tasks/task_1575999096/repo/python/servo/testing_commands.py", line 568, in format
    file.write(formatted.encode("utf-8"))
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/codecs.py", line 357, in write
    data, consumed = self.encode(object, self.errors)