Avoid re-evaluating expressions in filters and projections

This patterns shows up pretty often:

```sql
select expensive(col)
from t
where expensive(col)
```

A pathological case is variant / json:

```sql
select variant_get(col, 'key')
from t
from variant_get(col, 'key')
```

There's two issues here:
1. Until we solve projection pushdown (https://github.com/apache/datafusion/issues/14993) if `key` is not shredded we materialize the entire `col` and then extract `key` in a `ProjectionExec`.
2. Even once that is resolved, or in the case that `key` is not shredded evaluating `variant_get(col, 'key')` itself is expensive we still re-compute `variant_get(col, 'key')` twice: once for the filter and once for the projection.

Comienza leyendo el comportamiento de filtrado y proyección descrito en los ejemplos de SQL, incluidos ProjectionExec y el issue de projection-pushdown #14993. Determina cómo se representan y evalúan las expresiones repetidas, como variant_get(col, 'key'), y define la finalización como evitar la evaluación duplicada preservando al mismo tiempo los resultados de la consulta.

Escrito por el modelo de indexación a partir del texto del issue.