Tests: Use keepDataFolder flag in RunWithOpts to skip AdditionalExperimentCleanup in TEST_CASE_END_OVERRIDE

[MichaelHuth]

Sometimes a developer would like to diagnose panel states that were setup in a test case. Then it is unlucky if they are closed at the end of the test case.

We can store the keepDataFolder flag of RunWithOpts in a global to prevent the panel to be cleaned up at the end.
This induces possible errors reported from the WaveLeak checks but is good for diagnostics.