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(SpanToStr(result), "xyz");
    BOOST_CHECK_EQUAL(SpanToStr(sp), ")foo");
    input = "((a),(b),(c)),xxx";
    sp = input;
    result = Expr(sp);
    BOOST_CHECK_EQUAL(SpanToStr(result), "((a),(b),(c))");
    BOOST_CHECK_EQUAL(SpanToStr(sp), ",xxx");
    
    std::vector<Span<const char>> results;
    input = "xxx";
    results = Split(input, 'x');
    BOOST_CHECK_EQUAL(results.size(), 4U);
    BOOST_CHECK_EQUAL(SpanToStr(results[0]), "");
    BOOST_CHECK_EQUAL(SpanToStr(results[1]), "");
    BOOST_CHECK_EQUAL(SpanToStr(results[2]), "");
    BOOST_CHECK_EQUAL(SpanToStr(results[3]), "");
    input = "one#two#three";
    results = Split(input, '-');
    BOOST_CHECK_EQUAL(results.size(), 1U);
    BOOST_CHECK_EQUAL(SpanToStr(results[0]), "one#two#three");
    input = "one#two#three";
    results = Split(input, '#');
    BOOST_CHECK_EQUAL(results.size(), 3U);
    BOOST_CHECK_EQUAL(SpanToStr(results[0]), "one");
    BOOST_CHECK_EQUAL(SpanToStr(results[1]), "two");
    BOOST_CHECK_EQUAL(SpanToStr(results[2]), "three");
    input = "*foo*bar*";
    results = Split(input, '*');
    BOOST_CHECK_EQUAL(results.size(), 4U);
    BOOST_CHECK_EQUAL(SpanToStr(results[0]), "");