Revert of Turn off error resilience for VP9 if no spatial or temporal layers are configured and NACK is enabl… (patchset #1 id:40001 of https://codereview.webrtc.org/2532053002/ )

Reason for revert:
Increase in encode time larger than expected.

Original issue's description:
> Turn off error resilience for VP9 if no spatial or temporal layers are configured and NACK is enabled.
>
> Error resilience is currently always enabled for VP9 which reduces quality.
>
> BUG=webrtc:6783
>
> Committed: https://crrev.com/4eb03c76fa2320534d669fda2aabf800e7a6f579
> Cr-Commit-Position: refs/heads/master@{#15390}

TBR=stefan@webrtc.org,marpan@webrtc.org,mflodman@webrtc.org,marpan@google.com
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:6783

Review-Url: https://codereview.webrtc.org/2554403006
Cr-Commit-Position: refs/heads/master@{#15501}
diff --git a/webrtc/common_types.h b/webrtc/common_types.h
index dc7442c..2988bf9f 100644
--- a/webrtc/common_types.h
+++ b/webrtc/common_types.h
@@ -537,7 +537,7 @@
 // VP9 specific.
 struct VideoCodecVP9 {
   VideoCodecComplexity complexity;
-  bool resilienceOn;
+  int resilience;
   unsigned char numberOfTemporalLayers;
   bool denoisingOn;
   bool frameDroppingOn;