[booster] make optimizer argument optional for boost

[cwher]

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Close #3992.

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[github-actions]

The code coverage for the changed files is 88%.

Click me to view the complete report

Name                                                                  Stmts   Miss  Cover
-----------------------------------------------------------------------------------------
colossalai/booster/booster.py                                            63     10    84%
colossalai/booster/mixed_precision/fp16_torch.py                         46      2    96%
colossalai/booster/mixed_precision/mixed_precision_base.py                9      1    89%
colossalai/booster/plugin/gemini_plugin.py                              109      9    92%
colossalai/booster/plugin/low_level_zero_plugin.py                       94      8    91%
colossalai/booster/plugin/plugin_base.py                                 40     10    75%
colossalai/booster/plugin/torch_ddp_plugin.py                            63      3    95%
colossalai/booster/plugin/torch_fsdp_plugin.py                           97     13    87%
tests/test_autochunk/test_autochunk_diffuser/test_autochunk_unet.py      36     10    72%
-----------------------------------------------------------------------------------------
TOTAL                                                                   557     66    88%

[github-actions]

The code coverage for the changed files is 86%.

Click me to view the complete report

Name                                                                  Stmts   Miss  Cover
-----------------------------------------------------------------------------------------
colossalai/booster/booster.py                                            63     10    84%
colossalai/booster/mixed_precision/fp16_torch.py                         46      2    96%
colossalai/booster/mixed_precision/mixed_precision_base.py                9      1    89%
colossalai/booster/plugin/gemini_plugin.py                              110      9    92%
colossalai/booster/plugin/low_level_zero_plugin.py                       94      8    91%
colossalai/booster/plugin/plugin_base.py                                 40     10    75%
colossalai/booster/plugin/torch_ddp_plugin.py                            66      5    92%
colossalai/booster/plugin/torch_fsdp_plugin.py                           97     13    87%
colossalai/checkpoint_io/checkpoint_io_base.py                           66      9    86%
colossalai/checkpoint_io/general_checkpoint_io.py                       103      8    92%
colossalai/checkpoint_io/index_file.py                                   70     17    76%
colossalai/checkpoint_io/utils.py                                       241     45    81%
colossalai/zero/gemini/gemini_ddp.py                                    402     70    83%
tests/test_autochunk/test_autochunk_diffuser/test_autochunk_unet.py      36     10    72%
tests/test_checkpoint_io/test_general_checkpoint_io.py                  108      0   100%
-----------------------------------------------------------------------------------------
TOTAL                                                                  1551    217    86%

[github-actions]

The code coverage for the changed files is 14%.

Click me to view the complete report

Name                                                                  Stmts   Miss  Cover
-----------------------------------------------------------------------------------------
colossalai/booster/booster.py                                            63     63     0%
colossalai/booster/mixed_precision/fp16_torch.py                         46     46     0%
colossalai/booster/mixed_precision/mixed_precision_base.py                9      9     0%
colossalai/booster/plugin/gemini_plugin.py                              110    110     0%
colossalai/booster/plugin/low_level_zero_plugin.py                       94     94     0%
colossalai/booster/plugin/plugin_base.py                                 40     40     0%
colossalai/booster/plugin/torch_ddp_plugin.py                            66     66     0%
colossalai/booster/plugin/torch_fsdp_plugin.py                           97     97     0%
colossalai/checkpoint_io/checkpoint_io_base.py                           66     33    50%
colossalai/checkpoint_io/general_checkpoint_io.py                       103     82    20%
colossalai/checkpoint_io/index_file.py                                   70     48    31%
colossalai/checkpoint_io/utils.py                                       241    200    17%
colossalai/zero/gemini/gemini_ddp.py                                    402    348    13%
tests/test_autochunk/test_autochunk_diffuser/test_autochunk_unet.py      36     10    72%
-----------------------------------------------------------------------------------------
TOTAL                                                                  1443   1246    14%