zcash/zcash:
The `getmininginfo` RPC now omits `currentblockize` and `currentblocktx`
when a block was never assembled via RPC on this node during its current
process instantiation. The relevant RPCs are `generate` (regtest only) and
`getblocktemplate`. Blocks are also assembled when running the internal
miner (`zcashd -gen=1`), after the node mines its first block.
(cherry picked from commit bitcoin/bitcoin@fa178a6385)