Cap h264 fuzzer input to 200k.

Verified it no longer times out on the input that spawned the bug.

Bug: chromium:1005853
Change-Id: I5b0ab25aaefdc8b451b4d976b1c3b8f8d38f13e9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/153840
Reviewed-by: Benjamin Wright <benwright@webrtc.org>
Commit-Queue: Benjamin Wright <benwright@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29260}

test/fuzzers/h264_depacketizer_fuzzer.cc

@@ -11,6 +11,8 @@
 
 namespace webrtc {
 void FuzzOneInput(const uint8_t* data, size_t size) {
+  if (size > 200000)
+    return;
   RtpDepacketizerH264 depacketizer;
   RtpDepacketizer::ParsedPayload parsed_payload;
   depacketizer.Parse(&parsed_payload, data, size);