Audio VTS: Look for Audio policy config in all supported folders

audio_policy_configuration.xml can be loaded from the following places:
 - /system/etc/
 - /vendor/etc
 - /odm/etc
Nevertheless the config validation test was expecting it to be in
/vendor/etc exclusively.

This patch changes the test logic to:
 - look for the config files in all 3 folders
 - make sure the config is unique

Test: run the following script to check for regressions and test that
      invalid config make the test fail.
  (
  set -xe
  runVTS() { vts-tradefed run commandAndExit vts \
        --skip-all-system-status-check --primary-abi-only \
        --skip-preconditions --module VtsHalAudioV2_0Target \
        -t CheckConfig.audioPolicyConfigurationValidation; }

  echo "# Test valid config"
  runVTS

  echo "# Test multiple invalid match"
  adb shell touch /system/etc/audio_policy_configuration.xml
  ! runVTS
  adb shell rm /system/etc/audio_policy_configuration.xml

  echo "# Test multiple valid match"
  adb shell cp /{vendor,system}/etc/audio_policy_configuration.xml
  ! runVTS
  adb shell rm /system/etc/audio_policy_configuration.xml

  echo "# Test invalid config"
  adb shell sed -i /defaultOutputDevice/p /vendor/etc/audio_policy_configuration.xml
  ! runVTS
  adb shell sed -i '"/defaultOutputDevice/{p;N;d}"' /vendor/etc/audio_policy_configuration.xml

  echo "# Test that the test did not break the config"
  runVTS
  )

Bug: 64881365
Change-Id: I9db5e6f727d19fd654a3cc543a2aaab196682001
Signed-off-by: Kevin Rocard <krocard@google.com>