Minor: clean up the code regarding clippy (#8122)

Author: Weijun-H

datafusion/core/src/physical_optimizer/limited_distinct_aggregation.rs

@@ -57,7 +57,7 @@ impl LimitedDistinctAggregation {
             aggr.filter_expr().to_vec(),
             aggr.order_by_expr().to_vec(),
             aggr.input().clone(),
-            aggr.input_schema().clone(),
+            aggr.input_schema(),
         )
         .expect("Unable to copy Aggregate!")
         .with_limit(Some(limit));

datafusion/physical-plan/src/limit.rs

@@ -229,7 +229,7 @@ impl ExecutionPlan for GlobalLimitExec {
                     let remaining_rows: usize = nr - skip;
                     let mut skip_some_rows_stats = Statistics {
                         num_rows: Precision::Exact(remaining_rows),
-                        column_statistics: col_stats.clone(),
+                        column_statistics: col_stats,
                         total_byte_size: Precision::Absent,
                     };
                     if !input_stats.num_rows.is_exact().unwrap_or(false) {

datafusion/sql/src/statement.rs

@@ -1017,7 +1017,7 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
                 expr_to_columns(&filter_expr, &mut using_columns)?;
                 let filter_expr = normalize_col_with_schemas_and_ambiguity_check(
                     filter_expr,
-                    &[&[&scan.schema()]],
+                    &[&[scan.schema()]],
                     &[using_columns],
                 )?;
                 LogicalPlan::Filter(Filter::try_new(filter_expr, Arc::new(scan))?)