Followup from 🐛 Remove use of TestClass constructor RTBC .
PHPUnit changes the constructor for the TestCase several times. Its well accepted that logic should be in various setup methods instead of the constructor because its internal and the signature is subject to change but core instantiates TestCases's directly in some places which also breaks. This can cause testing errors or potential strange behaviors when TestCase is used or constructed in unusual ways.
Determine if static analysis can be added (or requested from upstream) to catch these sorts of odd uses of the class so they don't introduce false passes or strange test behaviors.