[SPARK-49943][PS] Remove timestamp_ntz_to_long from PythonSQLUtils

### What changes were proposed in this pull request?
Remove `timestamp_ntz_to_long` from `PythonSQLUtils`

### Why are the changes needed?
we no longer need to add internal functions in `PythonSQLUtils` for PySpark Classic

### Does this PR introduce _any_ user-facing change?
no

### How was this patch tested?
existing tests

### Was this patch authored or co-authored using generative AI tooling?
no

Closes #48437 from zhengruifeng/fun_cat_nzt.

Authored-by: Ruifeng Zheng <ruifengz@apache.org>
Signed-off-by: Ruifeng Zheng <ruifengz@apache.org>

python/pyspark/pandas/data_type_ops/datetime_ops.py

@@ -34,6 +34,7 @@
 )
 from pyspark.sql.utils import pyspark_column_op
 from pyspark.pandas._typing import Dtype, IndexOpsLike, SeriesOrIndex
+from pyspark.pandas.spark import functions as SF
 from pyspark.pandas.base import IndexOpsMixin
 from pyspark.pandas.data_type_ops.base import (
     DataTypeOps,
@@ -150,10 +151,7 @@ class DatetimeNTZOps(DatetimeOps):
     """
 
     def _cast_spark_column_timestamp_to_long(self, scol: Column) -> Column:
-        from pyspark import SparkContext
-
-        jvm = SparkContext._active_spark_context._jvm
-        return Column(jvm.PythonSQLUtils.castTimestampNTZToLong(scol._jc))
+        return SF.timestamp_ntz_to_long(scol)
 
     def astype(self, index_ops: IndexOpsLike, dtype: Union[str, type, Dtype]) -> IndexOpsLike:
         dtype, spark_type = pandas_on_spark_type(dtype)

python/pyspark/pandas/spark/functions.py

@@ -39,6 +39,10 @@ def _invoke_internal_function_over_columns(name: str, *cols: "ColumnOrName") ->
         return Column(sc._jvm.PythonSQLUtils.internalFn(name, _to_seq(sc, cols, _to_java_column)))
 
 
+def timestamp_ntz_to_long(col: Column) -> Column:
+    return _invoke_internal_function_over_columns("timestamp_ntz_to_long", col)
+
+
 def product(col: Column, dropna: bool) -> Column:
     return _invoke_internal_function_over_columns("pandas_product", col, F.lit(dropna))
 

sql/core/src/main/scala/org/apache/spark/sql/api/python/PythonSQLUtils.scala

@@ -143,9 +143,6 @@ private[sql] object PythonSQLUtils extends Logging {
     }
   }
 
-  def castTimestampNTZToLong(c: Column): Column =
-    Column.internalFn("timestamp_ntz_to_long", c)
-
   def unresolvedNamedLambdaVariable(name: String): Column =
     Column(internal.UnresolvedNamedLambdaVariable.apply(name))