Activate fluid models

[dkachuma]

This PR activates some fluid models in MultiFluidSelector.hpp only for CPU builds. The issue is that when activated for CUDA builds, these extra models cause compilation failures for some of the GHA pipelines. These are therefore currently being activated only for non-device builds.

• Some dangling debugging code is also cleaned up.
• A unit test is activated to test the different fluid models.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 53.70%. Comparing base (0f53ecd) to head (9449600).

Files	Patch %	Lines
...onents/constitutive/fluid/multifluid/PVTDriver.cpp	50.00%	1 Missing :warning:
...ompositional/models/NegativeTwoPhaseFlashModel.hpp	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #3123 +/- ## ======================================== Coverage 53.70% 53.70% ======================================== Files 1010 1010 Lines 85637 85639 +2 ======================================== + Hits 45990 45993 +3 + Misses 39647 39646 -1 ```

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