PR14085 backport https://github.com/bitcoin/bitcoin/pull/14085/files
ed12d5df1ba52b5ef3dd3799de26bb5e1d3fc654 index: Fix for indexers skipping genesis block. (Jim Posen)
Pull request description:
This fixes a bug where indexers would skip processing of the genesis block. Preserves the current behavior of omitting genesis block transaction from the index.
Backporter note: indeed this changes nothing about current behaviour, it
just prepares for BIP157 filters that want to index the genesis.