NetEq fuzzers: Set max length in BUILD config rather than in the code

This is the preferred way.

NOTRY=True

Bug: none
Change-Id: I305d4d9cb7b66e01427958e1416d672badd72af0
Reviewed-on: https://webrtc-review.googlesource.com/86948
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Commit-Queue: Henrik Lundin <henrik.lundin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23837}

test/fuzzers/neteq_rtp_fuzzer.cc

@@ -124,10 +124,6 @@ class FuzzRtpInput : public NetEqInput {
 }  // namespace
 
 void FuzzOneInputTest(const uint8_t* data, size_t size) {
-  // Limit the input size to 100000 bytes to avoid fuzzer timeout.
-  if (size > 100000)
-    return;
-
   std::unique_ptr<FuzzRtpInput> input(
       new FuzzRtpInput(rtc::ArrayView<const uint8_t>(data, size)));
   std::unique_ptr<AudioChecksum> output(new AudioChecksum);