message: Fix a possible crash.
  Summary:
  Fix a possible crash.
  We saw some crashes that might have been caused by this. No repro available,
  so this is not a confirmed fix.
diff: @@ -2224,8 +2224,10 @@ OatFile::~OatFile() = default;
  static std::unique_ptr<OatFile> parse_oatfile_impl(bool dex_files_only,
  ConstBuffer oatfile_buffer,
  const std::vector<DexInput>& dexes) {
  + constexpr size_t kOatElfOffset = 0x1000;
  +
  size_t oat_offset = 0;
  - if (oatfile_buffer.len >= sizeof(Elf32_Ehdr)) {
  + if (oatfile_buffer.len >= std::max(kOatElfOffset, sizeof(Elf32_Ehdr))) {
  Elf32_Ehdr header;
  memcpy(&header, oatfile_buffer.ptr, sizeof(Elf32_Ehdr));
  if (header.e_ident[0] == 0x7f &&
  @@ -2240,6 +2242,10 @@ static std::unique_ptr<OatFile> parse_oatfile_impl(bool dex_files_only,
  }
  }
  + if (oatfile_buffer.len < sizeof(OatHeader)) {
  + return nullptr;
  + }
  +
  auto header = OatHeader_Common::parse(oatfile_buffer);
  // TODO: do we need to handle endian-ness? I think all platforms we
  