Fix crash on missing parent blocks:

Historically we have some weird floating blocks back from Golang
times because AstroBWTv3 implemnentation was slow and in some
cases too slow to fit the 1s block window constantly. With latest
upstream merges from Kaspa the boomerang bounces back hard. It
will fail with:

KeyNotFound(GhostdagCompact/0/fefefefefefefefefefefefefefefefefefefefefefefefefefefefefefefefe)

It fails because block neither exist in Ghostdag nor Ghostdag
Compact. Since the block doesn't exist, we will assume blue
work to be 0 and return it as fallback.

Author: 0xA001113

consensus/src/processes/ghostdag/protocol.rs

@@ -99,7 +99,10 @@ impl<T: GhostdagStoreReader, S: RelationsStoreReader, U: ReachabilityService, V:
     pub fn find_selected_parent(&self, parents: impl IntoIterator<Item = Hash>) -> Hash {
         parents
             .into_iter()
-            .map(|parent| SortableBlock { hash: parent, blue_work: self.ghostdag_store.get_blue_work(parent).unwrap() })
+            .map(|parent| SortableBlock {
+                hash: parent,
+                blue_work: self.ghostdag_store.get_blue_work(parent).unwrap_or(spectre_math::Uint192([0, 0, 0])),
+            })
             .max()
             .unwrap()
             .hash