Revert of Reland "Move smoothing filter to common audio". (patchset #5 id:100001 of https://codereview.webrtc.org/2520003005/ )

Reason for revert:
Internal bots failed.

Original issue's description:
> Reland "Move smoothing filter to common audio".
>
> The original CL was this https://codereview.webrtc.org/2484153002/
>
> Due to failure with internal trial servers, it was reverted. This CL tries to reland it.
>
> BUG=webrtc:6443
>
> Committed: https://crrev.com/223641f1b903e41e77d88f03199b4cdb65255ec8
> Cr-Commit-Position: refs/heads/master@{#15227}

TBR=tommi@webrtc.org,solenberg@webrtc.org,terelius@webrtc.org,kjellander@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6443

Review-Url: https://codereview.webrtc.org/2529943002
Cr-Commit-Position: refs/heads/master@{#15228}

webrtc/modules/remote_bitrate_estimator/aimd_rate_control_unittest.cc

@@ -9,8 +9,8 @@
  */
 #include <memory>
 
+#include "webrtc/modules/audio_coding/audio_network_adaptor/smoothing_filter.h"
 #include "webrtc/modules/remote_bitrate_estimator/aimd_rate_control.h"
-#include "webrtc/system_wrappers/include/clock.h"
 #include "webrtc/test/gtest.h"
 
 namespace webrtc {