Hot fix air terminal sizing divide by zero

[mjwitte]

Pull request overview

Fixes divide by zero problem with new air terminal sizing code added in #6248. And adds protections in other potential problem spots. Should fix the integration coverage test failure for 5ZoneAirCooledWithDOASAirLoop.idf.

Work Checklist

Add to this list or remove from it as applicable. This is a simple templated set of guidelines.

• Title of PR should be user-synopsis style (clearly understandable in a standalone changelog context)
• At least one of the following appropriate labels must be added to this PR to be consumed into the changelog:
  • Defect: This pull request repairs a github defect issue. The github issue should be referenced in the PR description
  • Refactoring: This pull request includes code changes that don't change the functionality of the program, just perform refactoring
  • NewFeature: This pull request includes code to add a new feature to EnergyPlus
  • Performance: This pull request includes code changes that are directed at improving the runtime performance of EnergyPlus
  • DoNoPublish: This pull request includes changes that shouldn't be included in the changelog

Review Checklist

This will not be exhaustively relevant to every PR.

• Code style (parentheses padding, variable names)
• Functional code review (it has to work!)
• If defect, results of running current develop vs this branch should exhibit the fix
• CI status: all green or justified
• Performance: CI Linux results include performance check -- verify this

[Myoldmopar]

Alright, we should know about this one within an hour. It's all looking so freaking 🍏 📗 💚 🇬🇱 (the last one is Greenland, so still GREEN). Thanks for this quick fix @mjwitte. If you want to merge it in yourself you are welcome to when the debug build comes back happy. If I see it first I'll click merge.