Fix: calculate energy density matrix using 0.5(S^-1HD + DHS^-1)

[dyzheng]

Reminder

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• [ ] Have you added adequate unit tests and/or case tests for your pull request?
• [ ] Have you noticed possible changes of behavior below or in the linked issue?
• [ ] Have you explained the changes of codes in core modules of ESolver, HSolver, ElecState, Hamilt, Operator or Psi? (ignore if not applicable)

Linked Issue

This PR should be tested and check if the current code is wrong. Any one can repeat the error with multi-k calculation in rt-TDDFT MD simulation.

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What's changed?

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Any changes of core modules? (ignore if not applicable)

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[dyzheng]

Force of rt-TDDFT is still different with AIMD, both before and after this PR.

[mohanchen]

We will close this PR, but new PRs related to this topic are welcome