Use Ninja for emscripten build of llvm

[mcbarton]

Description

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

emsdk supports Ninja builds, so this PR switches the ci over the Ninja for hopefully smaller and faster emscripten llvm builds. I have cleared the cache of emscripten llvm builds to check I haven't broken anything. Once the ci passes this PR should be ok to merge.

Fixes # (issue)

Type of change

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• Bug fix
• New feature
• Requires documentation updates

Testing

Please describe the test(s) that you added and ran to verify your changes.

Checklist

• I have read the contribution guide recently

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.96%. Comparing base (ded27fb) to head (29f1496).
Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #433   +/-   ##
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  Coverage   70.96%   70.96%           
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  Files           9        9           
  Lines        3541     3541           
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  Hits         2513     2513           
  Misses       1028     1028           

[anutosh491]

I shall try this out locally and get back with the reviews.

[anutosh491]

Could you tell me how this is better than what we already have ? I tried ninja locally and also tried updating the recipe on emscripten-forge. The build took me exactly the same time.

[mcbarton]

@anutosh491 locally it won't really make much of a difference unless your low on disk space. Its good for CppInterOps ci since we get a smaller build directory, and therefore it takes up less space in the cache (which we have are all running low on).

[anutosh491]

I just approved the pr, though I think merging is blocked and conflicts are present.