Reland "Enable using a custom NetEqFactory in simulations"

This is a reland of 2a11b2451a4068746fa0c55fa210efd4a15e4423
There are no changes compared to the first attempt.

Original change's description:
> Enable using a custom NetEqFactory in simulations
>
> Bug: webrtc:11005
> Change-Id: I8a15f77953cbd3c29a75c7cfc77f926b138994b9
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/165580
> Commit-Queue: Ivo Creusen <ivoc@webrtc.org>
> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#30286}

TBR=kwiberg

Bug: webrtc:11005
Change-Id: I4aa377e05916bd23f8f63aece9d0e27731c80d3e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/166465
Commit-Queue: Ivo Creusen <ivoc@webrtc.org>
Reviewed-by: Ivo Creusen <ivoc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30319}

modules/audio_coding/neteq/tools/neteq_test.h

@@ -20,6 +20,7 @@
 #include "absl/types/optional.h"
 #include "api/audio_codecs/audio_decoder_factory.h"
 #include "api/neteq/neteq.h"
+#include "api/neteq/neteq_factory.h"
 #include "api/test/neteq_simulator.h"
 #include "modules/audio_coding/neteq/tools/audio_sink.h"
 #include "modules/audio_coding/neteq/tools/neteq_input.h"
@@ -83,6 +84,7 @@ class NetEqTest : public NetEqSimulator {
             rtc::scoped_refptr<AudioDecoderFactory> decoder_factory,
             const DecoderMap& codecs,
             std::unique_ptr<std::ofstream> text_log,
+            NetEqFactory* neteq_factory,
             std::unique_ptr<NetEqInput> input,
             std::unique_ptr<AudioSink> output,
             Callbacks callbacks);