Refit optimization

[wdykas]

What does this PR do ?

does some optimizations for refit. We were having super large cpu footprint before from gathering all the meta data.

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[copy-pr-bot]

This pull request requires additional validation before any workflows can run on NVIDIA's runners.

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[wdykas]

/ok to test a4a3380

[copy-pr-bot]

/ok to test a4a3380

@wdykas, there was an error processing your request: E2

See the following link for more information: https://docs.gha-runners.nvidia.com/cpr/e/2/

[wdykas]

/ok to test 0c417bd

[wdykas]

/ok to test 4acf40e

[svcnvidia-nemo-ci]

🔄 Merge queue validation started!

You can track the progress here: https://github.com/NVIDIA/Megatron-LM/actions/runs/23360848253