Add pipeline redirection support (#4594)

* redirection

* Remove commented-out

* fix tests

* more fixes

crates/nu-command/src/dataframe/test_dataframe.rs

@@ -72,6 +72,8 @@ pub fn test_dataframe(cmds: Vec<Box<dyn Command + 'static>>) {
             &mut stack,
             &block,
             PipelineData::new(Span::test_data()),
+            true,
+            true,
         ) {
             Err(err) => panic!("test eval error in `{}`: {:?}", example.example, err),
             Ok(result) => {