It would be nice if there was a way to tell compilers not to drop the lock stack and thus issue warnings when accessing a symbol that needs a lock inside `Assume`/`Assert`.

Hit by (at least): @ajtowns , @jnewbery , me.
BOOST_CHECK(!ParseFixedPoint("10000000000.00000001", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("-10000000000.00000009", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("10000000000.00000009", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("-99999999999.99999999", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("99999909999.09999999", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("92233720368.54775807", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("92233720368.54775808", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("-92233720368.54775808", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("-92233720368.54775809", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("1.1e", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("1.1e-", 8, &amount));
    BOOST_CHECK(!ParseFixedPoint("1.", 8, &amount));
    
    BOOST_CHECK(ParseFixedPoint("0.001", 3, &amount));
    BOOST_CHECK_EQUAL(amount, CAmount{1});
    BOOST_CHECK(!ParseFixedPoint("0.0009", 3, &amount));
    BOOST_CHECK(!ParseFixedPoint("31.00100001", 3, &amount));
    BOOST_CHECK(!ParseFixedPoint("31.0011", 3, &amount));
    BOOST_CHECK(!ParseFixedPoint("31.99999999", 3, &amount));
    BOOST_CHECK(!ParseFixedPoint("31.999999999999999999999", 3, &amount));
}
static void TestOtherThread(fs::path dirname, std::string lockname, bool *result)
{
    *result = LockDirectory(dirname, lockname);
}
#ifndef WIN32 
static constexpr char LockCommand = 'L';
static constexpr char UnlockCommand = 'U';
static constexpr char ExitCommand = 'X';
[[noreturn]] static void TestOtherProcess(fs::path dirname, std::string lockname, int fd)