Fixes issue #644 (for David's model only) by sorting on space name when merging thermal zones.  This is more a band aid than a real fix, different results may still occur if spaces are renamed. I think the actual problem has to do with instability in EnergyPlus given the geometry in this model.  There are other tests in the regression repository that exhibit similar behavior.  I will leave those to Kyle.

[#60780124]
Merge branch 'develop' of github.com:NREL/OpenStudio into develop