[refactor](opt) remove redundant use_default_implementation_for_nulls() of some BE codes

be/src/vec/functions/array/function_array_difference.h

@@ -66,8 +66,6 @@ class FunctionArrayDifference : public IFunction {
 
     size_t get_number_of_arguments() const override { return 1; }
 
-    bool use_default_implementation_for_nulls() const override { return true; }
-
     DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {
         DCHECK(is_array(arguments[0]))
                 << "argument for function: " << name << " should be DataTypeArray but it has type "

be/src/vec/functions/function_hll.cpp

@@ -152,8 +152,6 @@ class FunctionHllFromBase64 : public IFunction {
 
     size_t get_number_of_arguments() const override { return 1; }
 
-    bool use_default_implementation_for_nulls() const override { return true; }
-
     Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,
                         uint32_t result, size_t input_rows_count) const override {
         auto res_null_map = ColumnUInt8::create(input_rows_count, 0);

be/src/vec/functions/function_multi_same_args.h

@@ -34,8 +34,6 @@ class FunctionMultiSameArgs : public IFunction {
 
     String get_name() const override { return name; }
 
-    bool use_default_implementation_for_nulls() const override { return true; }
-
     bool is_variadic() const override { return true; }
 
     size_t get_number_of_arguments() const override { return 0; }

be/src/vec/functions/function_struct_element.cpp

@@ -47,8 +47,6 @@ class FunctionStructElement : public IFunction {
     // Get function name.
     String get_name() const override { return name; }
 
-    bool use_default_implementation_for_nulls() const override { return true; }
-
     size_t get_number_of_arguments() const override { return 2; }
 
     ColumnNumbers get_arguments_that_are_always_constant() const override { return {1}; }

be/src/vec/functions/function_time_value_to_field.cpp

@@ -47,8 +47,6 @@ class FunctionTimeValueToField : public IFunction {
         return std::make_shared<ToDataType>();
     }
 
-    bool use_default_implementation_for_nulls() const override { return true; }
-
     Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,
                         uint32_t result, size_t input_rows_count) const override {
         DCHECK_EQ(arguments.size(), 1);

be/src/vec/functions/function_totype.h

@@ -462,8 +462,6 @@ class FunctionStringOperateToNullType : public IFunction {
         return make_nullable(std::make_shared<typename Impl::ReturnType>());
     }
 
-    bool use_default_implementation_for_nulls() const override { return true; }
-
     Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,
                         uint32_t result, size_t input_rows_count) const override {
         auto null_map = ColumnUInt8::create(input_rows_count, 0);