[fix](Nereids) check avg in correctness_p0 (#25533)

regression-test/data/correctness_p0/test_avg.out

@@ -1,6 +1,12 @@
 -- This file is automatically generated. You should know what you did if you want to edit this
--- !select --
-9.18181818181868E14
+-- !sum --
+90900000000004950
+
+-- !count --
+99
+
+-- !avg --
+9.181818181818681E14
 
 -- !select2 --
 \N	\N

regression-test/suites/correctness_p0/test_avg.groovy

@@ -37,7 +37,9 @@ suite("test_avg") {
     for (i in range(1, 100)) {
         sql """ INSERT INTO ${tableName} values (10000000000000${i}) """
     }
-    qt_select """ SELECT AVG(c_bigint) FROM ${tableName} """
+    qt_sum """ SELECT SUM(c_bigint) FROM ${tableName} """
+    qt_count """ SELECT COUNT(c_bigint) FROM ${tableName} """
+    qt_avg """ SELECT AVG(c_bigint) FROM ${tableName} """
     sql""" DROP TABLE IF EXISTS ${tableName} """