GH-45301: [C++] Change PrimitiveArray ctor to protected

[mapleFU]

Rationale for this change

This patch handles the case in GH-45301, changing the ctor for PrimitiveArray to private.

What changes are included in this PR?

change the ctor for PrimitiveArray to private.

Are these changes tested?

Yes

Are there any user-facing changes?

This PR makes protected a constructor that was public. Calling this constructor outside of subclasses resulted in incorrect code.

• GitHub Issue: [C++] PrimitiveArrays cause segmentation faults in PrettyPrinter #45301

[github-actions]

⚠️ GitHub issue #45301 has been automatically assigned in GitHub to PR creator.

[mapleFU]

@pitrou @sjperkins I've trying to change ctor to protected, seems that this also works

[sjperkins]

Minor suggestion: a static Make factory method that calls MakeArray might be useful, but I wouldn't consider this important at all.

[mapleFU]

Minor suggestion: a static Make factory method that calls MakeArray might be useful, but I wouldn't consider this important at all.

From my aspects, MakeArray already does this, but feel free to re-add this

[sjperkins]

From my aspects, MakeArray already does this, but feel free to re-add this

Agreed, I don't think this should block this PR.

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 4 benchmarking runs that have been run so far on merge-commit b1e822a.

There were no benchmark performance regressions. 🎉

The full Conbench report has more details. It also includes information about 2 possible false positives for unstable benchmarks that are known to sometimes produce them.