[ADD] more test cases for inverse KFAC and fix bug in `KFAC.load_state_dict`

[runame]

Follow up to #156, sorry, missed a test case.

_Edit: Added even more test cases and discovered and fixed a bug in KFAC's load_state_dict function._

[coveralls]

Pull Request Test Coverage Report for Build 12120638039

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 45 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-2.6%) to 89.43%

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Files with Coverage Reduction	New Missed Lines	%
curvlinops/fisher.py	45	25.76%
<!--	Total:	45		-->

Totals
Change from base Build 12098234071:	-2.6%
Covered Lines:	1523
Relevant Lines:	1703

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💛 - Coveralls