[Tests] don't disable constructor calls to mockups of classes that extend intern...

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

Fixes the tests for the 2.3 branch as reported by @stof in #11176.