feat(fs/unstable): add chmod and chmodSync

[jbronder]

This PR adds the chmod and chmodSync APIs to @std/fs, which are functions intended to mirror Deno.chmod and Deno.chmodSync, respectively.

Towards #6255.

[codecov]

Codecov Report

Attention: Patch coverage is 51.72414% with 14 lines in your changes missing coverage. Please review.

Project coverage is 96.37%. Comparing base (b1b557e) to head (f429fff).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
fs/unstable_chmod.ts	51.72%	14 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6343      +/-   ##
==========================================
- Coverage   96.40%   96.37%   -0.04%     
==========================================
  Files         549      550       +1     
  Lines       41851    41880      +29     
  Branches     6348     6351       +3     
==========================================
+ Hits        40348    40362      +14     
- Misses       1463     1478      +15     
  Partials       40       40              

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[kt3k]

We can't use Deno specific features (such as Deno.create, Deno.remove, or Deno.makeTempDir) in testing as these test are also run in Node.js (also we can't use using as it's not supported yet in Node).

One way to work around it is to use node:fs APIs in testing which is supported by both Node and Deno. Another way would be first porting those necessary APIs to std/fs and use them in testing

[jbronder]

Ahh, I see. I'll start updating the tests. I appreciate the guidance.

[kt3k]

Thanks for updating the test. Now this looks perfect!