Move shared files in net/quic/ into net/quic/core/

net/quic/quic_crypto_framer_parse_message_fuzzer.cc

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <stddef.h>
-#include <stdint.h>
-
-#include "base/strings/string_piece.h"
-#include "net/quic/crypto/crypto_framer.h"
-
-// Entry point for LibFuzzer.
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  base::StringPiece crypto_input(reinterpret_cast<const char*>(data), size);
-  std::unique_ptr<net::CryptoHandshakeMessage> handshake_message(
-      net::CryptoFramer::ParseMessage(crypto_input));
-
-  return 0;
-}