fix test

Signed-off-by: Runji Wang <[email protected]>

e2e_test/streaming/time_window.slt

@@ -12,6 +12,9 @@ insert into t1 values
     (7, 1, 6, '2022-01-01 10:51:00'),
     (8, 3, 8, '2022-01-01 11:02:00');
 
+statement ok
+flush;
+
 statement ok
 create materialized view mv_tumble as
 select * from tumble(t1, created_at, interval '30' minute);
@@ -44,9 +47,6 @@ select uid, sum(v) as sum_v, window_start
 from hop(t1, created_at, interval '15' minute, interval '30' minute)
 group by window_start, uid;
 
-statement ok
-flush;
-
 query IITTT
 select row_id, uid, created_at, window_start, window_end
 from mv_tumble order by row_id, window_start;