resume() overwrites new config

[SuTanTank]

Checklist

1. I have searched related issues but cannot get the expected help.
2. I have read the FAQ documentation but cannot get the expected help.
3. The unexpected results still exist in the latest version.

Describe the Issue

In runner.resume(), meta is overwritten by the one loaded from the checkpoint. When saving new checkpoints, the wrong old config is saved instead of the new one.

Reproduction

1. train with config v1
2. save checkpoint (v1 is saved)
3. change config v1 -> v2
4. resume train (meta.config is still v1)
5. save checkpoint (bug here: v1 is saved)
6. resume train (got v1)

Bug fix #1886

[HAOCHENYE]

Good job! Thanks for your contribution~