Workgen workloads can take --verbose as a parameter, but when doing so the Workgen C++ code doesn't output any verbose messages.

There is the following verbose method to be used:

#define VERBOSE(runner, args)               \
    do {                                    \
        if ((runner)._context->_verbose)    \
            std::cout << args << std::endl; \
    } while (0)

But we do not set Context->_verbose to true anywhere at the moment. I traced back, and --verbose has never worked. Argument parsing from python that gets used to initialize the C++ structures was added in WT-5989 (c81160). I think that change missed initializing the Context::_verbose

This should be a simple fix.