Catalog assert-masked de-serializer invariants in the HDF5 library source

We are only interested in checks whose truth does depend on in-file bytes. In newer code(?), initialization helpers are used, which are still effective in release mode (`-DNDEBUG`).

Areas to check include:

- V2 B-trees
- Dataset chunk records
- Extensible arrays
- Fractal heaps
- Free-space managers
- Shared object-header messages
- Metadata-cache images

My cursory count suggests between 50 and 100 such instances, but I might have under- or double counted.