StringToAddress could end up evaluating an expression, which is a somewhat
unexpected behavior of a seemingly simple method. I rename it to
EvaluateAddressExpression and move it to the Target class, next to the standard
This functionality is now invoked via
execution_context->GetTargetPtr()->EvaluateAddressExpression(). To avoid null
checking the target pointer everywhere, I've added the eCommandRequiresTarget
flag to the commands which didn't have it, and which did not seem to be useful
without a target (disassemble && target modules list).