fix error of QuantizationTransformPassV2 when has condition block (#48190)

* fix error of QuantizationTransformPassV2 when has condition block

* fix error

python/paddle/fluid/contrib/slim/quantization/quantization_pass.py

@@ -2481,11 +2481,6 @@ class QuantizationTransformPassV2(QuantizationTransformPass):
         self.create_var_map = {}
         self.create_op_map = {}
 
-        # marked the variable which has been dequantized.
-        self.dequantized_vars = collections.OrderedDict()
-        self.persistable_vars = []
-        self.processed_vars = []
-
     def _quant_preprocess(self, op_node):
         user_skipped = False
         if isinstance(self._skip_pattern, list):
@@ -2627,6 +2622,10 @@ class QuantizationTransformPassV2(QuantizationTransformPass):
         ), 'graph must be the instance of IrGraph.'
         if self._is_test is None:
             self._is_test = graph.is_test()
+        # marked the variable which has been dequantized.
+        self.dequantized_vars = collections.OrderedDict()
+        self.persistable_vars = []
+        self.processed_vars = []
 
         self.persistable_vars = [
             p.name() for p in graph.all_persistable_nodes()