Address all comments and fix unit test failure

Author: c21

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/grouping.scala

@@ -217,9 +217,9 @@ case class Grouping(child: Expression) extends Expression with Unevaluable
     Examples:
       > SELECT name, _FUNC_(), sum(age), avg(height) FROM VALUES (2, 'Alice', 165), (5, 'Bob', 180) people(age, name, height) GROUP BY cube(name, height);
         Alice	0	2	165.0
-        Bob	0	5	180.0
         Alice	1	2	165.0
         NULL	3	7	172.5
+        Bob	0	5	180.0
         Bob	1	5	180.0
         NULL	2	2	165.0
         NULL	2	5	180.0

sql/catalyst/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala

@@ -3875,8 +3875,6 @@ class SQLConf extends Serializable with Logging {
 
   def enableTwoLevelAggMap: Boolean = getConf(ENABLE_TWOLEVEL_AGG_MAP)
 
-  def enableTwoLevelAggMapPartialOnly: Boolean = getConf(ENABLE_TWOLEVEL_AGG_MAP_PARTIAL_ONLY)
-
   def enableVectorizedHashMap: Boolean = getConf(ENABLE_VECTORIZED_HASH_MAP)
 
   def useObjectHashAggregation: Boolean = getConf(USE_OBJECT_HASH_AGG)

sql/core/src/main/scala/org/apache/spark/sql/execution/aggregate/HashAggregateExec.scala

@@ -671,7 +671,7 @@ case class HashAggregateExec(
       if (modes.forall(mode => mode == Partial || mode == PartialMerge)) {
         true
       } else {
-        !conf.enableTwoLevelAggMapPartialOnly
+        !conf.getConf(SQLConf.ENABLE_TWOLEVEL_AGG_MAP_PARTIAL_ONLY)
       }
 
     isSupported && isNotByteArrayDecimalType && isEnabledForAggModes