telemetry_unittests failing on 3 builders

Tests failed:
telemetry/internal/image_processing/screen_finder_unittest/ScreenFinderTest/testBasicFunctionality
telemetry/internal/image_processing/video_file_frame_generator_unittest/VideoFileFrameGeneratorTest/testVideoFileFrameGeneratorSkipFrames
telemetry/internal/image_processing/video_file_frame_generator_unittest/VideoFileFrameGeneratorTest/testVideoFileFrameGeneratorSuccess


Builders failed on: 
- Win 7 Tests x64 (1): 
- Win7 Tests (1): 
- Win7 Tests (dbg)(1): 
  https://build.chromium.org/p/chromium.win/builders/Win%207%20Tests%20x64%20%281%29
 https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%281%29
 https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29

E.g. first failing build:
https://uberchromegw.corp.google.com/i/chromium.win/builders/Win%207%20Tests%20x64%20%281%29/builds/29807


Revision Range:
https://test-results.appspot.com/revision_range?start=507677&end=507699

Example failures:

https://chromium-swarm.appspot.com/task?id=3920a6c8d1a4e710&refresh=10&show_raw=1&wide_logs=true


[1/2] telemetry.internal.image_processing.screen_finder_unittest.ScreenFinderTest.testBasicFunctionality failed unexpectedly 0.0010s:
  Traceback (most recent call last):
    File "e:\b\s\w\ir\third_party\catapult\telemetry\telemetry\decorators.py", line 208, in wrapper
      func(*args, **kwargs)
    File "e:\b\s\w\ir\third_party\catapult\telemetry\telemetry\internal\image_processing\screen_finder_unittest.py", line 52, in testBasicFunctionality
      sf = self._GetScreenFinder('screen_3_frames.mov')
    File "e:\b\s\w\ir\third_party\catapult\telemetry\telemetry\internal\image_processing\screen_finder_unittest.py", line 40, in _GetScreenFinder
      fg = self.VideoFileFrameGenerator(vid)
    File "e:\b\s\w\ir\third_party\catapult\telemetry\telemetry\internal\image_processing\video_file_frame_generator.py", line 43, in __init__
      raise frame_generator.FrameReadError('Not enough frames in capture.')
  FrameReadError: Not enough frames in capture.