'Fixing' a few TODOs by removing them.

The one with enum.IntFlag is not feasible. An attempt is done here:
https://webrtc-review.googlesource.com/c/src/+/133884

It requires re-writing QualityAssessment to Python3 which is too much
work for little benefit. (I tried, but couldn't get the unit-tests to
pass for both 2 and 3.)

The second one is not a real todo.

TBR=alessiob@webrtc.org
NOPRESUBMIT=True
Bug=None
NOTRY=True

Change-Id: Ia25817533cd504c30490f86e4058f0b2d59dd39c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/133908
Commit-Queue: Alex Loiko <aleloi@webrtc.org>
Reviewed-by: Alex Loiko <aleloi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27715}

modules/audio_processing/test/py_quality_assessment/quality_assessment/annotations.py

@@ -33,7 +33,6 @@ class AudioAnnotationsExtractor(object):
   """Extracts annotations from audio files.
   """
 
-  # TODO(aleloi): change to enum.IntEnum when py 3.6 is available.
   class VadType(object):
     ENERGY_THRESHOLD = 1  # TODO(alessiob): Consider switching to P56 standard.
     WEBRTC_COMMON_AUDIO = 2  # common_audio/vad/include/vad.h

modules/audio_processing/test/py_quality_assessment/quality_assessment/eval_scores.py

@@ -350,7 +350,6 @@ class TotalHarmonicDistorsionScore(EvaluationScore):
     self._input_frequency = None
 
   def _Run(self, output_path):
-    # TODO(aleloi): Integrate changes made locally.
     self._CheckInputSignal()
 
     self._LoadTestedSignal()