Function rewrite_tablesample 

pub fn rewrite_tablesample(sql: &str) -> SqlResult<String>

Rewrites Spark TABLESAMPLE(n PERCENT) to DataFusion-compatible form.

-- Input
SELECT * FROM t TABLESAMPLE (10 PERCENT)

-- Output
SELECT * FROM t TABLESAMPLE (10 PERCENT)

DataFusion supports TABLESAMPLE natively (since v38), so this is mostly a passthrough with validation.