Use FakeRenderer when fuzzing

Do not fuzz with real renderer because it is merely frame copying and
doesn't exercise different control flows. This CL also improved fuzzing
performance and fixed a memory leak.

Bug: chromium:952606, chromium:1009077, chromium:1009073
Change-Id: I77c6f2581db82bfd95edb18e5f0e541a94c78208
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/156620
Commit-Queue: Benjamin Wright <benwright@webrtc.org>
Reviewed-by: Benjamin Wright <benwright@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29522}

test/fuzzers/utils/rtp_replayer.h

@@ -28,7 +28,6 @@
 #include "test/null_transport.h"
 #include "test/rtp_file_reader.h"
 #include "test/test_video_capturer.h"
-#include "test/video_renderer.h"
 
 namespace webrtc {
 namespace test {