Fix CodeGen V2 for zero-length array

[ttreyer]

Summary

Fix issue #295

1. Replace the recursive validate_size template with a non-recursive one, making CodeGen compile
2. Process zero-length array as containers, so no object size is left unread in the data buffer
3. Enable the zero-length array test

Is it ok to process zero-length array as container? I had to modify the test's results to all 0 sizes. Is this the behavior expected? Or should it report an exclusive size of 1 for the Foo struct?

Test plan

The example provided in #295 now passes successfully and has been enabled in the integration tests.

$ build/test/integration/integration_test_runner --gtest_filter='OidIntegration.arrays_member_int0' --verbose --preserve --enable-feature type-graph

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (cbeafba) 62.38% compared to head (cff773b) 62.41%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #453 +/- ## ========================================== + Coverage 62.38% 62.41% +0.02% ========================================== Files 123 123 Lines 12007 12006 -1 Branches 1956 1955 -1 ========================================== + Hits 7491 7493 +2 + Misses 3571 3570 -1 + Partials 945 943 -2 ```

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