fix: prevent race condition in heap profiler

[rohitpruthi-google]

This pull request fixes a race condition in the heap profiler that could cause
heap.profile() to return an empty profile if called immediately after heap.start().

The issue was that heap.profile() could be called before the V8 heap profiler had
collected any samples, resulting in a blank snapshot.

This change fixes the issue by introducing a polling mechanism in the C++ addon. The
GetAllocationProfile function now waits for the profiler to collect at least one sample
before returning a profile. This ensures that heap.profile() always returns a valid
profile.

Fixes #310

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 42.17%. Comparing base (dead429) to head (85d15c1).
⚠️ Report is 19 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #311      +/-   ##
==========================================
+ Coverage   41.92%   42.17%   +0.24%     
==========================================
  Files          14       14              
  Lines        2092     2101       +9     
  Branches       42       42              
==========================================
+ Hits          877      886       +9     
  Misses       1197     1197              
  Partials       18       18              

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