[C++] ScanNode is not using the filter expression

The ScanNode can not apply predicate push-down, it seems the are some fragments that are not able to use or setting up properly the filter expression. 

auto options = std::make_shared<ScanOptions>();
options->filter = filter_expression;
compute::MakeExecNode("scan", plan.get(), {}, ScanNodeOptions{dataset, options})); 

Also, if the ScanOptions doesn't have a projection expression the code just crash and I think I should create a default expression to include all the fields from the dataset schema.