EnforceDistribution: adjust_input_keys_ordering returns Transformed::yes unconditionally for non-join plans #21946

Describe the bug

adjust_input_keys_ordering in EnforceDistribution returns Transformed::yes unconditionally in the default else branch (line 421), even when requirements.data is empty and no changes were made. This triggers unnecessary with_new_children rebuilds on every node in the plan tree for non-join/non-aggregate queries.

To Reproduce

Any query without joins or aggregates (e.g. a simple SELECT * FROM table WHERE ... ORDER BY ... LIMIT N) will have every node in the tree rebuilt during adjust_input_keys_ordering, even though no key reordering is needed.

Expected behavior

When requirements.data is empty (no parent key ordering to push down) and the plan node is not a join/aggregate/projection/repartition/window, adjust_input_keys_ordering should return Transformed::no to skip the rebuild.

Impact

For plans with custom ExecutionPlan nodes whose with_new_children is expensive (e.g. nodes that re-evaluate cost functions on rebuild), this causes significant overhead. CPU profiling showed this contributes to unnecessary work in the physical optimizer chain.

Proposed fix

Add an early return with Transformed::no when requirements.data.is_empty() in the default else branch of adjust_input_keys_ordering. Will submit a PR.