Remove implicit downcast in producer_fec_fuzzer.cc.

Speculative fix for DrFuzz.

BUG=
TBR=stefan@webrtc.org

Review URL: https://codereview.webrtc.org/1664453002 .

Cr-Original-Commit-Position: refs/heads/master@{#11465}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 2ab815779c7c8dd1d9b4378da3e834e6f80f0889
diff --git a/test/fuzzers/producer_fec_fuzzer.cc b/test/fuzzers/producer_fec_fuzzer.cc
index 4cea7fc..77336e6 100644
--- a/test/fuzzers/producer_fec_fuzzer.cc
+++ b/test/fuzzers/producer_fec_fuzzer.cc
@@ -45,15 +45,13 @@
       producer.AddRtpPacketAndGenerateFec(packet.get(), payload_size,
                                           rtp_header_length);
     }
-    uint16_t num_fec_packets = producer.NumAvailableFecPackets();
-    std::vector<RedPacket*> fec_packets;
+    const size_t num_fec_packets = producer.NumAvailableFecPackets();
     if (num_fec_packets > 0) {
-      fec_packets =
+      std::vector<RedPacket*> fec_packets =
           producer.GetFecPackets(kRedPayloadType, 99, 100, rtp_header_length);
       RTC_CHECK_EQ(num_fec_packets, fec_packets.size());
-    }
-    for (RedPacket* fec_packet : fec_packets) {
-      delete fec_packet;
+      for (RedPacket* fec_packet : fec_packets)
+        delete fec_packet;
     }
   }
 }