Multi-call RPC (#6195)

* Removing duplicated pending state accessors in miner.

* Merge miner+client call.

* Multicall & multicall RPC.

* Sensible defaults.

* Fix tests.

sync/src/block_sync.rs

@@ -267,7 +267,7 @@ impl BlockDownloader {
 				BlockStatus::Bad => {
 					return Err(BlockDownloaderImportError::Invalid);
 				},
-				BlockStatus::Unknown => {
+				BlockStatus::Unknown | BlockStatus::Pending => {
 					headers.push(hdr.as_raw().to_vec());
 					hashes.push(hash);
 				}

sync/src/chain.rs

@@ -995,7 +995,7 @@ impl ChainSync {
 				BlockStatus::Queued => {
 					trace!(target: "sync", "New hash block already queued {:?}", hash);
 				},
-				BlockStatus::Unknown => {
+				BlockStatus::Unknown | BlockStatus::Pending => {
 					new_hashes.push(hash.clone());
 					if number > max_height {
 						trace!(target: "sync", "New unknown block hash {:?}", hash);