Specify order in .slt test

datafusion/sqllogictest/test_files/union.slt

@@ -766,13 +766,13 @@ SELECT NULL WHERE FALSE;
 query error DataFusion error: type_coercion\ncaused by\nError during planning: Incompatible inputs for Union: Previous inputs were of type List(.*), but got incompatible type List(.*) on column 'x'
 SELECT make_array(2) x UNION ALL SELECT make_array(now()) x;
 
-query ?
+query ? rowsort
 select make_array(arrow_cast(2, 'UInt8')) x UNION ALL SELECT make_array(arrow_cast(-2, 'Int8')) x;
 ----
 [-2]
 [2]
 
-query ?
+query ? rowsort
 select make_array(make_array(1)) x UNION ALL SELECT make_array(arrow_cast(make_array(-1), 'LargeList(Int8)')) x;
 ----
 [[-1]]