fix: avoid WRITE+EXEC for CPUID check

[orlp]

Our MacOS runners were failing due to invalid permissions for the mmap call. This may fix it.

[codecov]

Codecov Report

Attention: Patch coverage is 12.50000% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 35.88%. Comparing base (fd41e03) to head (7882db9).
Report is 36 commits behind head on main.

Files	Patch %	Lines
py-polars/polars/_cpu_check.py	12.50%	7 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main   #15912       +/-   ##
===========================================
- Coverage   80.38%   35.88%   -44.50%     
===========================================
  Files        1263     1364      +101     
  Lines      165368   167713     +2345     
  Branches        0     3032     +3032     
===========================================
- Hits       132927    60184    -72743     
- Misses      32441   107062    +74621     
- Partials        0      467      +467     

Flag	Coverage Δ
python	35.88% <12.50%> (?)
rust	35.88% <12.50%> (?)

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