Revert: deserialize stored transactions in a rayon thread (#4933)

* Revert: deserialize stored transactions in a rayon thread

* Add a TODO for the reverted bug fix

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

zebra-state/src/service/finalized_state/disk_format/block.rs

@@ -231,21 +231,12 @@ impl FromDisk for Transaction {
     fn from_bytes(bytes: impl AsRef<[u8]>) -> Self {
         let bytes = bytes.as_ref();
 
-        let mut tx = None;
-
-        // # Performance
-        //
-        // Move CPU-intensive deserialization cryptography into the rayon thread pool.
-        // This avoids blocking the tokio executor.
-        rayon::in_place_scope_fifo(|scope| {
-            scope.spawn_fifo(|_scope| {
-                tx = Some(bytes.as_ref().zcash_deserialize_into().expect(
-                    "deserialization format should match the serialization format used by IntoDisk",
-                ));
-            });
-        });
-
-        tx.expect("scope has already run")
+        // TODO: skip cryptography verification during transaction deserialization from storage,
+        //       or do it in a rayon thread (ideally in parallel with other transactions)
+        bytes
+            .as_ref()
+            .zcash_deserialize_into()
+            .expect("deserialization format should match the serialization format used by IntoDisk")
     }
 }