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.
CAmount deduction = target_fee - current_fee;
        if (deduction > 0) {
            
            
            mempool_txn.vout[fee_output.value()].nValue -= deduction;
            
            input_errors.clear();
            assert(SignTransaction(mempool_txn, &keystore, input_coins, nHashType, input_errors));
            current_fee = target_fee;
        }
    }
    return {mempool_txn, current_fee};
}
CMutableTransaction TestChain100Setup::CreateValidMempoolTransaction(const std::vector<CTransactionRef>& input_transactions,
                                                                     const std::vector<COutPoint>& inputs,
                                                                     int input_height,
                                                                     const std::vector<CKey>& input_signing_keys,
                                                                     const std::vector<CTxOut>& outputs,
                                                                     bool submit)
{
    CMutableTransaction mempool_txn = CreateValidTransaction(input_transactions, inputs, input_height, input_signing_keys, outputs, std::nullopt, std::nullopt).first;
    
    if (submit) {
        LOCK(cs_main);
        const MempoolAcceptResult result = m_node.chainman->ProcessTransaction(MakeTransactionRef(mempool_txn));
        assert(result.m_result_type == MempoolAcceptResult::ResultType::VALID);
    }
    return mempool_txn;
}
CMutableTransaction TestChain100Setup::CreateValidMempoolTransaction(CTransactionRef input_transaction,