Removing obsolete app remoting test app and code

This code is unlikely to be used again and I wanted to clear out some
cruft to make the signaling migration work a bit simpler, thus I'm
removing these files.

We should also consider whether to remove the ChromotingTestDriver or to
adapt it for the new signaling solution.  I think it could be useful but
that is for another CL in the future.

Change-Id: I9a87b9d413ddf706f8570a7fb294a06361a2f141
Reviewed-on: https://chromium-review.googlesource.com/c/1469526
Commit-Queue: Yuwei Huang <yuweih@chromium.org>
Auto-Submit: Joe Downing <joedow@chromium.org>
Reviewed-by: Yuwei Huang <yuweih@chromium.org>
Cr-Commit-Position: refs/heads/master@{#631831}
25 files changed