Co-authored-by: Andre Sailer <andre.philippe.sailer@cern.ch>

Use of nicely named variables such as $p may clash with local user
environments. A similar change was implemented in ROOT a long time
ago:
https://github.com/root-project/root/commit/bba80a143655a4aac63cb5adb2e9f2d73bcd9566

Unknown pragma error

there are many overlaps in the model, regardless of unit system used, but sometimes a track can get stuck, this avoids it for the test case

tbb gives issue for tests with key4hep stack

Revert "Allow to set MeanExcEnergy, MeanEnergyPerIonPair and BirksConstant in G4Materials ionisation parameters"

This reverts commit 990be5d0.

This reverts commit e2a0dc27.