GCC 12 fails to compile signature.cpp due to -Wstringop-overread

Trying to compile with GCC 12.1.1 (current Fedora Rawhide) yields this failure:

```
In file included from /home/test/shipilev-jdk/src/hotspot/share/utilities/globalDefinitions_gcc.hpp:35,
                 from /home/test/shipilev-jdk/src/hotspot/share/utilities/globalDefinitions.hpp:35,
                 from /home/test/shipilev-jdk/src/hotspot/share/memory/allocation.hpp:29,
                 from /home/test/shipilev-jdk/src/hotspot/share/classfile/classLoaderData.hpp:28,
                 from /home/test/shipilev-jdk/src/hotspot/share/precompiled/precompiled.hpp:34:
In function 'const void* memchr(const void*, int, size_t)',
    inlined from 'int SignatureStream::scan_type(BasicType)' at /home/test/shipilev-jdk/src/hotspot/share/runtime/signature.cpp:343:32,
    inlined from 'void SignatureStream::next()' at /home/test/shipilev-jdk/src/hotspot/share/runtime/signature.cpp:373:19,
    inlined from 'void SignatureIterator::do_parameters_on(T*) [with T = Fingerprinter]' at /home/test/shipilev-jdk/src/hotspot/share/runtime/signature.hpp:635:41,
    inlined from 'void SignatureIterator::do_parameters_on(T*) [with T = Fingerprinter]' at /home/test/shipilev-jdk/src/hotspot/share/runtime/signature.hpp:629:6,
    inlined from 'void Fingerprinter::compute_fingerprint_and_return_type(bool)' at /home/test/shipilev-jdk/src/hotspot/share/runtime/signature.cpp:169:19:
/usr/include/string.h:102:27: error: 'void* __builtin_memchr(const void*, int, long unsigned int)' specified bound [18446744073709486082, 0] exceeds maximum object size 9223372036854775807 [-Werror=stringop-overread]
  102 | return __builtin_memchr (__s, __c, __n);
      | ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors
```