Track Apache Arrow mimalloc allocations

[pablogsal]

Hook the arrow_mi_malloc_aligned, arrow_mi_realloc_aligned, and arrow_mi_free symbols introduced in Apache Arrow 25 so Memray can attribute Arrow logical allocations instead of seeing only mimalloc mmap arenas.

Scope: Linux Arrow 25+ builds using mimalloc with interposable arrow_mi_* wrapper symbols. Official PyArrow 25 Linux wheels satisfy these requirements.

The hooks are re-resolved when libraries are loaded after Tracker initialization. To avoid crossing independent statically linked mimalloc instances, Memray patches only the ELF object that defines the selected wrapper; if multiple providers are loaded, later providers are left untracked rather than routed through the wrong allocator.

Tests cover loading Arrow before tracking, during tracking, and between Tracker sessions, plus isolation between multiple providers.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.42%. Comparing base (f70db81) to head (22a7ed1).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #943      +/-   ##
==========================================
- Coverage   92.45%   92.42%   -0.03%     
==========================================
  Files         101      102       +1     
  Lines       13211    13260      +49     
  Branches      477      477              
==========================================
+ Hits        12214    12256      +42     
- Misses        997     1004       +7     

Flag	Coverage Δ
cpp	92.42% <100.00%> (-0.03%)	⬇️
python_and_cython	92.42% <100.00%> (-0.03%)	⬇️

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[godlygeek]

Looks like apache/arrow#41128 has landed. Should we move forward with this, @pablogsal ?

[pablogsal]

Ready for rock and roll

[godlygeek]

LGTM. I've fixed the coverage to require arrow>=25.0, and I tweaked the wording on the news item to something I think users will understand better (from "Track logical allocations" to "Track individual allocations", to make it clearer that what we were seeing previously was the allocations of the arenas and not the individual allocations from those arenas).

Other than that, this LGTM. Thanks @pablogsal!

[godlygeek]

I do imagine we might eventually want to be able to interpose these on macOS as well, but if Arrow doesn't support that yet, that's a problem for another day.