[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* [legacy] remove outdated codes of pipeline (#4692)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* [legacy] remove outdated colo tensor (#4694)

* [legacy] remove outdated colo tensor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* [legacy] move outdated zero to legacy (#4696)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

tests/test_cluster/test_process_group_mesh.py

@@ -7,8 +7,8 @@ from colossalai.testing import spawn
 
 
 def check_process_group_mesh_with_gpc():
-    from colossalai.context import ParallelMode
-    from colossalai.core import global_context as gpc
+    from colossalai.legacy.context import ParallelMode
+    from colossalai.legacy.core import global_context as gpc
 
     DP_DIM, PP_DIM, TP_DIM = 0, 1, 2
     pg_mesh = ProcessGroupMesh(1, 2, 2)
@@ -138,7 +138,7 @@ def run_dist(rank, world_size, port):
                       port=port,
                       host='localhost')
     # TODO(ver217): this function should be removed when gpc is removed
-    check_process_group_mesh_with_gpc()
+    # check_process_group_mesh_with_gpc()
     check_process_group_mesh_with_cases()