clean code

python/paddle/jit/dy2static/partial_program.py

@@ -108,15 +108,6 @@ def __get__(self, instance, cls):
         return val
 
 
-def _change_is_test_status(program, is_test):
-    # change all `is_test` attributes
-    for block in program.blocks:
-        for op in block.ops:
-            if op.has_attr('is_test'):
-                op._set_attr('is_test', is_test)
-    return program
-
-
 class ProgramInfo:
     """
     A helper class to recoder Program information