Fix run inference bug for standalone executor (#44340)

python/paddle/fluid/executor.py

@@ -1404,10 +1404,14 @@ class Executor(object):
                     return False
 
                 # Unsupported case 3: data parallel
-                if program._is_data_parallel == True and len(
+                if program._is_data_parallel and len(
                         program._get_places(place, program._places)) != 1:
                     return False
 
+                # Unsupported case 4: inference
+                if program._is_inference:
+                    return False
+
                 return True
             else:
                 if isinstance(program._graph, compiler.CompiledProgram):