Update smoke test for atree inlining

[fxamacker]

Closes #343 Updates epics #292 Updates #296 #297

This PR updates smoke test to test mutation of child container:

• existing child retrieved from parent array/map
• new child appened/inserted to parent array
• existing child set in parent array/map
• new child set in parent map

This PR also added flag -slabcheck to enable in-memory slab validation and slab serialization validation. This check is time-consuming so it is disabled by default.

While at it, also refactored smoke tests.

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• [ ] Targeted PR against main branch
• [x] Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• [x] Code follows the standards mentioned here
• [x] Updated relevant documentation
• [x] Re-reviewed Files changed in the Github PR explorer
• [x] Added appropriate labels

[codecov-commenter]

Codecov Report

All modified lines are covered by tests :white_check_mark:

Comparison is base (0fc8f74) 62.58% compared to head (25dbc3e) 62.58%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## feature/array-map-inlining #348 +/- ## =========================================================== Coverage 62.58% 62.58% =========================================================== Files 15 15 Lines 10559 10559 =========================================================== Hits 6608 6608 Misses 3008 3008 Partials 943 943 ```

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