Fix the unit test error and adjust the condition for fetching objects

[dashanji]

What do these changes do?

The e2e repartition is caused by the error as follows.

 start to get ddf                                                                                                                                                                                       │
│ /usr/local/lib/python3.10/site-packages/vineyard/core/client.py:536: UserWarning: Migrating object ObjectID <"o0024772b04722d27"> from another vineyard instance 18446744073709551615                  │
│   warnings.warn(                                                                                                                                                                                       │
│ Traceback (most recent call last):                                                                                                                                                                     │
│   File "/job.py", line 55, in <module>                                                                                                                                                                 │
│     data = client.get(vineyard.ObjectID(gid),                                                                                                                                                          │
│   File "/usr/local/lib/python3.10/site-packages/vineyard/core/client.py", line 582, in get                                                                                                             │
│     return get(self, object_id, name, resolver, fetch, **kwargs)                                                                                                                                       │
│   File "/usr/local/lib/python3.10/site-packages/vineyard/core/resolver.py", line 235, in get                                                                                                           │
│     obj = client.get_object(object_id)                                                                                                                                                                 │
│   File "/usr/local/lib/python3.10/site-packages/vineyard/core/client.py", line 451, in get_object                                                                                                      │
│     return self._fetch_object(object_id)                                                                                                                                                               │
│   File "/usr/local/lib/python3.10/site-packages/vineyard/core/client.py", line 540, in _fetch_object                                                                                                   │
│     return self._ipc_client.get_object(object_id, fetch=True)                                                                                                                                          │
│ vineyard._C.InvalidException: Invalid: IPC error at /work/v6d/src/common/util/protocols.cc:2072: global objects cannot be directly migrated 

Add a juadgement before fetching object to fix that.

Related issue number

Fixes #1679