GitLab

[Cleanup] Remove unused pcm files.

* single_user_demo_mono_16kHz.pcm was never used, apparently.
* speechmusic_mono_16kHz.pcm was only referenced by one test,
  which was removed here:
https://codereview.chromium.org/194813002

TEST=content_unittests

Bug: chromium:331030
Change-Id: I4b77c264729db411d38f5d0568496cb76a2ce4be
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1882308Reviewed-by: Tommi <tommi@chromium.org>
Commit-Queue: Yves Gerey <yvesg@google.com>
Cr-Commit-Position: refs/heads/master@{#709864}