Fix spurious failures in `DurationTest`

[joka921]

There was a bug in a comparator in a test helper function which lead to spurious failures in a randomized test. This is now fixed.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.38%. Comparing base (5007401) to head (fec9c90). Report is 2 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1451 +/- ## ========================================== + Coverage 89.37% 89.38% +0.01% ========================================== Files 345 345 Lines 24886 24886 Branches 3309 3309 ========================================== + Hits 22242 22245 +3 + Misses 1503 1502 -1 + Partials 1141 1139 -2 ```

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[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud