Platform-independent reflection list sort in Single_crystal

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Free-form text area

Please describe what your PR is adding in terms of features or bugfixes:

In the same line of thinking as #2272, this PR is meant to bring identical algorithmic behaviour across Unix/Windows, based on sorting Single_crystal reflection lists.

(Thinking is again that across operating systems, qsort() behaviour for 'equal' elements is not well-defined.)

I have run a few test-cases e.g. with templateLaue (which is a relatively 'clean' Single_crystal system) - here the output still differs for ~ 20 in 1e6 particles when comparing between macOS Arm and Windows Intel...

More investigations of where the differences lie may come later.

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Development OS / boundary conditions

Please describe what OS you developed and tested your additions on, and if any special dependencies are required:

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PR Checklist for contributing to McStas/McXtrace

For a coherent and useful contribution to McStas/McXtrace, please fill in relevant parts of the checklist:

• My contribution includes patches to an existing component file

  • I have used the mcdoc utility and rendered a reasonable documentation page for the component (please attach as screenshot in comments!)
  • I have ensured that basic use of the component is OK (e.g. an instrument using it compiles?)
  • I have used the mctest utility to test one or more instruments making use of the component (please attach mcviewtest report as screenshot in comments)
  • I have used the mcrun --c-lint "linter" and followed advice to remove most / all warnings that are raised

• My contribution contains something else

  • Explanation is added in free form text above or below the checklist

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McXtrace conda/Windows fails "as normal" since complex number handling is not fully in place for MSVC in McXtrace

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McStas Single_crystal test looks good:

McStas Single_crystal_process test looks good:

McXtrace Single_crystal test looks mostly good (with exception of Windows, as expected - and SOLEIL_PX2a should probably be looked at independently (same indication for earlier 'nightlies')