address the comment

Signed-off-by: yisaer <disxiaofei@163.com>

executor/stale_txn_test.go

@@ -915,20 +915,9 @@ func (s *testStaleTxnSerialSuite) TestStaleSelect(c *C) {
 	tk.MustExec("insert into t values (4, 5)")
 	time.Sleep(10 * time.Millisecond)
 	tk.MustQuery("execute s").Check(staleRows)
-
-	// test dynamic timestamp stale select
-	time3 := time.Now()
 	tk.MustExec("alter table t add column d int")
 	tk.MustExec("insert into t values (4, 4, 4)")
 	time.Sleep(tolerance)
-	time4 := time.Now()
-	staleRows = testkit.Rows("1 <nil>", "2 <nil>", "3 <nil>", "4 5")
-	tk.MustQuery(fmt.Sprintf("select * from t as of timestamp CURRENT_TIMESTAMP(3) - INTERVAL %d MICROSECOND", time4.Sub(time3).Microseconds())).Check(staleRows)
-
-	// test prepared dynamic timestamp stale select
-	time5 := time.Now()
-	tk.MustExec(fmt.Sprintf(`prepare v from "select * from t as of timestamp CURRENT_TIMESTAMP(3) - INTERVAL %d MICROSECOND"`, time5.Sub(time3).Microseconds()))
-	tk.MustQuery("execute v").Check(staleRows)
 
 	// test point get
 	time6 := time.Now()