message: test: Fix fuzzer compilation on macOS
  fixes
diff: @@ -332,7 +332,7 @@ public:
  return 0;
  }
  std::memcpy(buf, random_bytes.data(), random_bytes.size());
  - if (AdditionOverflow((uint64_t)fuzzed_file->m_offset, random_bytes.size())) {
  + if (AdditionOverflow(fuzzed_file->m_offset, (int64_t)random_bytes.size())) {
  return fuzzed_file->m_fuzzed_data_provider.ConsumeBool() ? 0 : -1;
  }
  fuzzed_file->m_offset += random_bytes.size();
  @@ -343,7 +343,7 @@ public:
  {
  FuzzedFileProvider* fuzzed_file = (FuzzedFileProvider*)cookie;
  const ssize_t n = fuzzed_file->m_fuzzed_data_provider.ConsumeIntegralInRange<ssize_t>(0, size);
  - if (AdditionOverflow(fuzzed_file->m_offset, n)) {
  + if (AdditionOverflow(fuzzed_file->m_offset, (int64_t)n)) {
  return fuzzed_file->m_fuzzed_data_provider.ConsumeBool() ? 0 : -1;
  }
  fuzzed_file->m_offset += n;
  