Revert "Expose AV1 encoder&decoder from Android SDK."

This reverts commit fedd5029c584e9dc1352434b62a30cd8af2889d8.

Reason for revert: Speculative revert due to crashes in downstream tests on Android.

Original change's description:
> Expose AV1 encoder&decoder from Android SDK.
>
> Bug: None
> Change-Id: Ie32be36da498d4bed2a3cf51aa6abc8838e42da1
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/212024
> Reviewed-by: Xavier Lepaul‎ <xalep@webrtc.org>
> Commit-Queue: Yura Yaroshevich <yura.yaroshevich@gmail.com>
> Cr-Commit-Position: refs/heads/master@{#33743}

TBR=alessiob@webrtc.org,mflodman@webrtc.org,yura.yaroshevich@gmail.com,xalep@webrtc.org

Change-Id: I76171087d1998b9d7573c2b86b1cf9ed65154bbf
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: None
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/215324
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33753}

sdk/android/src/java/org/webrtc/MediaCodecUtils.java

@@ -91,7 +91,6 @@ class MediaCodecUtils {
     switch (type) {
       case VP8:
       case VP9:
-      case AV1:
         return new HashMap<String, String>();
       case H264:
         return H264Utils.getDefaultH264Params(highProfile);