[legacy] clean up legacy code (#4743)

* [legacy] remove outdated codes of pipeline (#4692)

* [legacy] remove cli of benchmark and update optim (#4690)

* [legacy] remove cli of benchmark and update optim

* [doc] fix cli doc test

* [legacy] fix engine clip grad norm

* [legacy] remove outdated colo tensor (#4694)

* [legacy] remove outdated colo tensor

* [test] fix test import

* [legacy] move outdated zero to legacy (#4696)

* [legacy] clean up utils (#4700)

* [legacy] clean up utils

* [example] update examples

* [legacy] clean up amp

* [legacy] fix amp module

* [legacy] clean up gpc (#4742)

* [legacy] clean up context

* [legacy] clean core, constants and global vars

* [legacy] refactor initialize

* [example] fix examples ci

* [example] fix examples ci

* [legacy] fix tests

* [example] fix gpt example

* [example] fix examples ci

* [devops] fix ci installation

* [example] fix examples ci

examples/tutorial/opt/opt/colossalai_zero.py

@@ -2,7 +2,7 @@ try:
     from colossalai.zero.shard_utils import TensorShardStrategy
 except ImportError:
     # colossalai > 0.2.8
-    from colossalai.zero.legacy import TensorShardStrategy
+    from colossalai.legacy.zero import TensorShardStrategy
 
 zero = dict(model_config=dict(shard_strategy=TensorShardStrategy(),
                               tensor_placement_policy="auto",