Revert of Properly report number of quality downscales in stats. (patchset #11 id:220001 of https://codereview.webrtc.org/2564373002/ )

Reason for revert:
Breaks perf tests

Original issue's description:
> Properly report number of quality downscales in stats.
>
> A regression was introduced in 876222f that caused these stats to
> be reported incorrectly. This used to be only implemented for VP8
> but should now be available for all codecs.
>
> BUG=webrtc:6860
>
> Review-Url: https://codereview.webrtc.org/2564373002
> Cr-Commit-Position: refs/heads/master@{#15673}
> Committed: 0c8c538835

TBR=asapersson@webrtc.org,stefan@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6860

Review-Url: https://codereview.webrtc.org/2586783003
Cr-Commit-Position: refs/heads/master@{#15678}

webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc

@@ -466,7 +466,7 @@ bool SimulcastEncoderAdapter::SupportsNativeHandle() const {
 VideoEncoder::ScalingSettings SimulcastEncoderAdapter::GetScalingSettings()
     const {
   // Turn off quality scaling for simulcast.
-  if (!Initialized() || NumberOfStreams(codec_) != 1)
+  if (NumberOfStreams(codec_) != 1)
     return VideoEncoder::ScalingSettings(false);
   return streaminfos_[0].encoder->GetScalingSettings();
 }