When compiling without external signer support, the resulted `bench_bitcoin.exe` fails on Windows:
```
>.\bench_bitcoin.exe -filter=AddrManSelectByNetwork
Error: bad optional access
```

Steps to reproduce the failure:
- cross compiling on Ubuntu 22.04:
```
$ make -j $(nproc) -C depends HOST=x86_64-w64-mingw32 NO_QT=1
$ ./autogen.sh
$ ./configure CONFIG_SITE=$PWD/depends/x86_64-w64-mingw32/share/config.site --disable-external-signer
$ make -j $(nproc)
```
- compiling natively on Windows:

Apply the diff as follows:
```diff
--- a/build_msvc/bitcoin_config.h.in
+++ b/build_msvc/bitcoin_config.h.in
@@ -41,9 +41,6 @@
 /* Define this symbol to enable ZMQ functions */
 #define ENABLE_ZMQ 1
 
-/* define if external signer support is enabled (requires Boost::Process) */
-#define ENABLE_EXTERNAL_SIGNER /**/
-
 /* Define to 1 if you have the declaration of `be16toh', and to 0 if you
    don't. */
 #define HAVE_DECL_BE16TOH 0
```
Then
```
>py -3 build_msvc\msvc-autogen.py
>msbuild build_msvc\bitcoin.sln -property:Configuration=Release -verbosity:minimal
>src\bench_bitcoin.exe -filter=AddrManSelectByNetwork
Error: bad optional access
```

---

The failure does not manifest itself when running `bench_bitcoin.exe` using Wine on Linux.
BOOST_CHECK_EQUAL(HexStr(in_u), out_exp);
        BOOST_CHECK_EQUAL(HexStr(in_s), out_exp);
        BOOST_CHECK_EQUAL(HexStr(in_b), out_exp);
    }
    {
        auto input = std::string();
        for (size_t i=0; i<256; ++i) {
            input.push_back(static_cast<char>(i));
        }
        auto hex = HexStr(input);
        BOOST_TEST_REQUIRE(hex.size() == 512);
        static constexpr auto hexmap = std::string_view("0123456789abcdef");
        for (size_t i = 0; i < 256; ++i) {
            auto upper = hexmap.find(hex[i * 2]);
            auto lower = hexmap.find(hex[i * 2 + 1]);
            BOOST_TEST_REQUIRE(upper != std::string_view::npos);
            BOOST_TEST_REQUIRE(lower != std::string_view::npos);
            BOOST_TEST_REQUIRE(i == upper*16 + lower);
        }
    }
}
BOOST_AUTO_TEST_CASE(span_write_bytes)
{
    std::array mut_arr{uint8_t{0xaa}, uint8_t{0xbb}};
    const auto mut_bytes{MakeWritableByteSpan(mut_arr)};
    mut_bytes[1] = std::byte{0x11};
    BOOST_CHECK_EQUAL(mut_arr.at(0), 0xaa);
    BOOST_CHECK_EQUAL(mut_arr.at(1), 0x11);
}
BOOST_AUTO_TEST_CASE(util_Join)