chore: add Darwin and Windows OS's to node test runner

[jbronder]

Addresses #6636. This PR adds Windows and MacOS the matrix.os variable to expand the CI workflow of the Node test runner.

[codecov]

Codecov Report

Attention: Patch coverage is 7.69231% with 12 lines in your changes missing coverage. Please review.

Project coverage is 94.62%. Comparing base (2001bae) to head (367b5c4).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
fs/_get_fs_flag.ts	7.69%	12 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6711      +/-   ##
==========================================
- Coverage   94.65%   94.62%   -0.03%     
==========================================
  Files         576      576              
  Lines       47059    47070      +11     
  Branches     6608     6608              
==========================================
- Hits        44543    44542       -1     
- Misses       2474     2485      +11     
- Partials       42       43       +1     

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[jbronder]

Some of the @std/fs APIs are throwing when running tests with deno task test:node under the windows-latest. Should updates to those affected tests be addressed in separate, forthcoming PR(s)?

[kt3k]

Should updates to those affected tests be addressed in separate, forthcoming PR(s)?

We generally don't merge PRs to main which makes CI check red. Can you try to address those issues in this PR?

[jbronder]

That makes sense, I'll take a look.

[jbronder]

Quick progress update: I decided to tackle writeFile(Sync) APIs. I'm addressing one API set at a time. I did end up making some modifications to the getWriteFsFlag function to handle Windows differently from MacOS and Linux. This is documented in the function in comments. I'm imagining that writeTextFile(Sync) would be similar.