Fix table alias parsing regression in 0.31.0 by backing out redshift column definition list (#827)

* Fix table alias parsing regression

* Revert "Support redshift's columns definition list for system information functions (#769)"

This reverts commit c35dcc93a7.

src/test_utils.rs

@@ -185,7 +185,6 @@ pub fn table(name: impl Into<String>) -> TableFactor {
         name: ObjectName(vec![Ident::new(name.into())]),
         alias: None,
         args: None,
-        columns_definition: None,
         with_hints: vec![],
     }
 }