Address leftover comments from #3091

[IvoDD]

Reference Issues/PRs

Addresses leftover comments from #3091

What does this implement or fix?

Adds testing improvements and deduplication changes. Doesn't change any logic.

Also adds a couple of makefile commands to test-cpp-repidcheck and to bench-cpp-build

Any other comments?

Checklist

Checklist for code changes...

• Have you updated the relevant docstrings, documentation and copyright notice?
• Is this contribution tested against all ArcticDB's features?
• Do all exceptions introduced raise appropriate error messages?
• Are API changes highlighted in the PR description?
• Is the PR labelled as enhancement or bug so it appears in autogenerated release notes?

[claude]

ArcticDB Code Review Summary

Test/build-only refactor addressing leftover comments from #3091 — extracts the column-builder helpers (make_single_block_column, make_regular_blocks_column, make_irregular_blocks_column, block-size generators) into the shared util/test/test_utils.hpp, deduplicating copies across test_column.cpp, rapidcheck_column.cpp, and benchmark_column.cpp; converts bound_search/gallop_bracket static_asserts into requires clauses with equivalent constraints; splits IteratorSkipsEmptyBlocks into two focused tests; and adds test-cpp-rapidcheck(-debug) / bench-cpp-build Makefile targets.

Verified: helper templates are correctly inline/template (no ODR issues), all consumers include test_utils.hpp, the new Makefile targets map to existing CMake targets (arcticdb_rapidcheck_tests, benchmarks), constraint clauses match the removed asserts, and the no-release-notes label is correctly applied. No correctness, memory, or compatibility concerns.

Minor: cpp/arcticdb/util/test/test_utils.hpp no longer ends with a trailing newline. This may fail make lint-check in CI — add a final newline.