Use Ninja to build llvm in the ci (osx and Ubuntu)

[mcbarton]

Description

Please include a summary of changes, motivation and context for this PR.

My local testing on an osx arm Macbook found an 35% reduction in the size of the build folder when using Ninja to build llvm. This should help reduce the pressure on the cache. Supposedly Ninja is faster so we should see a speed in the llvm build when we have to rebuild the cache. If the ci passes then all Ubuntu and MacOS builds should be cleared from the cache before merging.

Fixes # (issue)

Type of change

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• Bug fix
• New feature
• Requires documentation updates

Testing

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Checklist

• I have read the contribution guide recently

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.85%. Comparing base (c446c3e) to head (78a655f).
Report is 1 commits behind head on main.

Additional details and impacted files

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  Coverage   70.85%   70.85%           
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  Files           9        9           
  Lines        3538     3538           
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  Hits         2507     2507           
  Misses       1031     1031           

[anutosh491]

Thanks, I think this is nice. I would have also preferred ninja for the emscripten build but I remember there were some reasons why we switched from ninja to cmake on emscripten-forge. I guess we just had some trouble using ninja. I need to try again.
Having it on osx and ubuntu is a good start.

[mcbarton]

@anutosh491 Ninja works now. I have tried it and plan to put in another PR for the emscripten build once the deployment PR is merged.