fs: validate position argument before length === 0 early return

[geeksilva97]

Move position validation upwards to match documented behavior.

Fixes #62638

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.76%. Comparing base (68d7b6f) to head (de1c243).
⚠️ Report is 517 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #62674      +/-   ##
==========================================
- Coverage   89.77%   89.76%   -0.02%     
==========================================
  Files         673      697      +24     
  Lines      203820   215153   +11333     
  Branches    39175    41184    +2009     
==========================================
+ Hits       182987   193136   +10149     
- Misses      13152    14202    +1050     
- Partials     7681     7815     +134     

Files with missing lines	Coverage Δ
lib/fs.js	98.19% <100.00%> (+<0.01%)	⬆️
lib/internal/fs/promises.js	92.94% <100.00%> (-5.79%)	⬇️

... and 277 files with indirect coverage changes

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