`Column::from_qualified_name` result is potentially feature-set dependent

[findepi]

Column::from_qualified_name uses different implementation of parse_identifiers_normalized / parse_identifiers depending on whether sql feature is enabled.

It is assume that these implementation are behaviorally different, or may be different in the future.

Let's now consider a crate X that uses DataFusion with sql feature disabled and it depends on particular behavior of Column::from_qualified_name.

If the crate is used in a bigger project which causes sql feature to be enabled, the result is unpredictable to X. The app may not work correctly even though each component works and all its tests pass.