[c++] Trivial parameterizes in test/common.cc

[johnkerl]

Issue and/or context: As tracked on issue #2407 / [sc-51048].

Changes:

Up until now the number of rows in arrow-schema/arrow-data for dataframe setup from Python/R to C++ has had 3 slots. On #2785 it will necessarily have 5. This PR parameterizes some hard-coded values of 3 to now reference n, after int n = 3.

Similarly, this PR replaces a hard-coded within-function 1000 to a new parameter dim_max for use by callers, who will need explicit construction access to test resize logic for upcoming PRs on #2407.

Notes for Reviewer:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.03%. Comparing base (bdba3c3) to head (d93cdf8).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2910      +/-   ##
==========================================
+ Coverage   89.88%   90.03%   +0.15%     
==========================================
  Files          37       37              
  Lines        3925     3925              
==========================================
+ Hits         3528     3534       +6     
+ Misses        397      391       -6     

Flag	Coverage Δ
python	90.03% <ø> (+0.15%)	⬆️

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Components	Coverage Δ
python_api	90.03% <ø> (+0.15%)	⬆️
libtiledbsoma	∅ <ø> (∅)