add .slt test case

Author: haohuaijin

datafusion/sqllogictest/test_files/subquery_sort.slt

@@ -51,6 +51,25 @@ EXPLAIN SELECT c1 FROM (SELECT c1 FROM sink_table ORDER BY c2)
 logical_plan TableScan: sink_table projection=[c1]
 physical_plan DataSourceExec: file_groups={1 group: [[WORKSPACE_ROOT/testing/data/csv/aggregate_test_100.csv]]}, projection=[c1], file_type=csv, has_header=true
 
+statement ok
+SET datafusion.sql_parser.enable_subquery_sort_elimination = false;
+
+query TT
+EXPLAIN SELECT c1 FROM (SELECT c1 FROM sink_table ORDER BY c2) AS ttt
+----
+logical_plan
+01)SubqueryAlias: ttt
+02)--Projection: sink_table.c1
+03)----Sort: sink_table.c2 ASC NULLS LAST
+04)------TableScan: sink_table projection=[c1, c2]
+physical_plan
+01)ProjectionExec: expr=[c1@0 as c1]
+02)--SortExec: expr=[c2@1 ASC NULLS LAST], preserve_partitioning=[false]
+03)----DataSourceExec: file_groups={1 group: [[WORKSPACE_ROOT/testing/data/csv/aggregate_test_100.csv]]}, projection=[c1, c2], file_type=csv, has_header=true
+
+statement ok
+RESET datafusion.sql_parser.enable_subquery_sort_elimination;
+
 
 # Do not remove ordering when it's with limit