Merge #7933: Fix OOM when deserializing UTXO entries with invalid length

1e44169 Add tests for CCoins deserialization (Pieter Wuille)
5d0434d Fix OOM bug: UTXO entries with invalid script length (Pieter Wuille)
4bf631e CDataStream::ignore Throw exception instead of assert on negative nSize. (Patrick Strateman)
4f87af6 Treat overly long scriptPubKeys as unspendable (Pieter Wuille)
f8e6fb1 Introduce constant for maximum CScript length (Pieter Wuille)