Remove unused audio_e2e_harness.cc and infrastructure.

webrtc/tools/e2e_quality/audio/README

-The tools here run an end-to-end audio quality test on Linux using PulseAudio.
-
-INSTALLATION
-The test depends on PulseAudio virtual devices (null sinks). Without additional
-arguments, run_audio_test.py expects a pair of sinks named "capture" and
-"render". To create these devices at machine startup, place the provided
-default.pa file in ~/.pulse. Alternately, the "pacmd" commands therein can be
-run on the command-line to create the devices.
-
-Similarly, place the provided daemon.conf file in ~/.pulse to use high quality
-resampling in PulseAudio. This will reduce the resampling impact on the outcome
-of the test.
-
-Build all WebRTC targets as usual (or just the audio_e2e_harness target) to
-generate the VoiceEngine harness.
-
-USAGE
-Run run_audio_test.py to start. The script has reasonable defaults and will
-use the expected location of audio_e2e_harness. Some settings will usually
-be provided by the user, particularly the comparison tool command-line and
-regular expression to extract the quality metric.
-
-An example command-line, run from trunk/
-
-webrtc/tools/e2e_quality/audio/run_audio_test.py \
---input=data/voice_engine/audio_short16.pcm --output=e2e_audio_out.pcm \
---codec=L16 --compare="comparison-tool" --regexp="(\d\.\d{3})"