add test for model weights equality when fault-tolerant training

[awaelchli]

What does this PR do?

Extends a test by asserting equality of model weights when comparing a full training run with one that got interrupted and resumed.

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[codecov]

Codecov Report

Merging #9481 (ca43bed) into master (0cb5508) will decrease coverage by 4%.
The diff coverage is n/a.

❗ Current head ca43bed differs from pull request most recent head fac3c9b. Consider uploading reports for the commit fac3c9b to get more accurate results

@@           Coverage Diff           @@
##           master   #9481    +/-   ##
=======================================
- Coverage      93%     89%    -4%     
=======================================
  Files         180     180            
  Lines       15066   15066            
=======================================
- Hits        13986   13373   -613     
- Misses       1080    1693   +613     

[tchaton]

Dope !

[ethanwharris]

LGTM, small comment