Revert of Setting up an RTP input fuzzer for NetEq (patchset #2 id:20001 of https://codereview.webrtc.org/2315633002/ )

Reason for revert:
Broke all Chromium libFuzzer builds
https://bugs.chromium.org/p/chromium/issues/detail?id=645069

Original issue's description:
> Setting up an RTP input fuzzer for NetEq
>
> This CL introduces a new fuzzer target neteq_rtp_fuzzer that
> manipulates the RTP header fields before inserting the packets into
> NetEq. A few helper classes are also introduced.
>
> BUG=webrtc:5447
> NOTRY=True
>
> Committed: https://crrev.com/2d273f1e97cd5030ed1686f27ce1118291b66395
> Cr-Commit-Position: refs/heads/master@{#14103}

TBR=ivoc@webrtc.org,kjellander@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:5447

Review-Url: https://codereview.webrtc.org/2328483002
Cr-Commit-Position: refs/heads/master@{#14131}

webrtc/modules/audio_coding/neteq/tools/neteq_input.h

@@ -65,9 +65,7 @@ class NetEqInput {
   // time).
   virtual void AdvanceOutputEvent() = 0;
 
-  // Returns true if the source has come to an end. An implementation must
-  // eventually return true from this method, or the test will end up in an
-  // infinite loop.
+  // Returns true if the source has come to an end.
   virtual bool ended() const = 0;
 
   // Returns the RTP header for the next packet, i.e., the packet that will be