Merge #19562: test: Fix fuzzer compilation on macOS

c8992e8959 test: Fix fuzzer compilation on macOS fixes #19557 (freenancial)

Pull request description:

  fixes #19557

  Before the fix:
  ```
  ➜  bitcoin git:(fix-fuzzer-macos) make
  Making all in src
    CXX      test/fuzz/addition_overflow-addition_overflow.o
  In file included from test/fuzz/addition_overflow.cpp:7:
  ./test/fuzz/util.h:335:13: error: no matching function for call to 'AdditionOverflow'
          if (AdditionOverflow((uint64_t)fuzzed_file->m_offset, random_bytes.size())) {
              ^~~~~~~~~~~~~~~~
  ./test/fuzz/util.h:201:16: note: candidate template ignored: deduced conflicting types for parameter 'T' ('unsigned long long' vs. 'unsigned long')
  NODISCARD bool AdditionOverflow(const T i, const T j) noexcept
                 ^
  ./test/fuzz/util.h:346:13: error: no matching function for call to 'AdditionOverflow'
          if (AdditionOverflow(fuzzed_file->m_offset, n)) {
              ^~~~~~~~~~~~~~~~
  ./test/fuzz/util.h:201:16: note: candidate template ignored: deduced conflicting types for parameter 'T' ('long long' vs. 'long')
  NODISCARD bool AdditionOverflow(const T i, const T j) noexcept
                 ^
  ```

  After the fix:
  ```
  ➜  bitcoin git:(fix-fuzzer-macos) ./configure --enable-fuzz --with-sanitizers=fuzzer,address,undefined CC=/usr/local/opt/llvm/bin/clang CXX=/usr/local/opt/llvm/bin/clang++ --disable-asm && make clean && make -j5
  ...
  ...
    CXXLD    test/fuzz/uint256_deserialize
  Making all in doc/man
  make[1]: Nothing to be done for `all'.
  make[1]: Nothing to be done for `all-am'.
  ```

ACKs for top commit:
  fanquake:
    ACK c8992e8959 - tested that compiling works on macOS.
  MarcoFalke:
    review ACK c8992e8959

Tree-SHA512: 965cdc61b30db0e2209c91b29f0d42de927a9a5b85e1e70f22d1452e0955f876726c7a8c1d1a5f448f12bf24eec3000802071cd4ae28d8605343fd43d174ca84

src/test/fuzz/util.h

@@ -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;