Reland "Default enable delay adaptation during DTX."

This is a reland of 59bdcbe3c97ac52f73b6b18aaed8db84d42b233f

Original change's description:
> Default enable delay adaptation during DTX.
>
> Bug: webrtc:10736
> Change-Id: I5dcc431211c6c1c89b4d7d1ab07b23d63c0550d3
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/201385
> Reviewed-by: Ivo Creusen <ivoc@webrtc.org>
> Commit-Queue: Jakob Ivarsson <jakobi@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#32999}

Bug: webrtc:10736
Change-Id: I8fc83e8b3fa6c122dcf706f0cae1b1a2e28555aa
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/202033
Reviewed-by: Ivo Creusen <ivoc@webrtc.org>
Commit-Queue: Jakob Ivarsson <jakobi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33004}
diff --git a/modules/audio_coding/neteq/neteq_impl_unittest.cc b/modules/audio_coding/neteq/neteq_impl_unittest.cc
index c66a0e2..a073d82 100644
--- a/modules/audio_coding/neteq/neteq_impl_unittest.cc
+++ b/modules/audio_coding/neteq/neteq_impl_unittest.cc
@@ -987,15 +987,6 @@
   EXPECT_TRUE(neteq_->RegisterPayloadType(kPayloadType,
                                           SdpAudioFormat("opus", 48000, 2)));
 
-  // Insert one packet (decoder will return speech).
-  EXPECT_EQ(NetEq::kOK, neteq_->InsertPacket(rtp_header, payload));
-
-  // Insert second packet (decoder will return CNG).
-  payload[0] = 1;
-  rtp_header.sequenceNumber++;
-  rtp_header.timestamp += kPayloadLengthSamples;
-  EXPECT_EQ(NetEq::kOK, neteq_->InsertPacket(rtp_header, payload));
-
   const size_t kMaxOutputSize = static_cast<size_t>(10 * kSampleRateKhz);
   AudioFrame output;
   AudioFrame::SpeechType expected_type[8] = {
@@ -1012,11 +1003,20 @@
       50 * kSampleRateKhz,
       10 * kSampleRateKhz};
 
+  // Insert one packet (decoder will return speech).
+  EXPECT_EQ(NetEq::kOK, neteq_->InsertPacket(rtp_header, payload));
+
   bool muted;
   EXPECT_EQ(NetEq::kOK, neteq_->GetAudio(&output, &muted));
   absl::optional<uint32_t> last_timestamp = neteq_->GetPlayoutTimestamp();
   ASSERT_TRUE(last_timestamp);
 
+  // Insert second packet (decoder will return CNG).
+  payload[0] = 1;
+  rtp_header.sequenceNumber++;
+  rtp_header.timestamp += kPayloadLengthSamples;
+  EXPECT_EQ(NetEq::kOK, neteq_->InsertPacket(rtp_header, payload));
+
   // Lambda for verifying the timestamps.
   auto verify_timestamp = [&last_timestamp, &expected_timestamp_increment](
                               absl::optional<uint32_t> ts, size_t i) {