```
Add deserialization fuzzing of SnapshotMetadata (utxo_snapshot).
Increase fuzzing coverage.
```
Backport of core PR18314.
The commit 117a706faba586f2095f97cf630b709b3e29a947:
https://github.com/bitcoin/bitcoin/pull/18314/commits/117a706faba586f2095f97cf630b709b3e29a947
is not ported as this function has been removed from our codebase (was
dead code, see D5992.