Attempt to fix withdrawals sync issue - write withdrawals to RLP in B…

…lock (as well as BlockBodies)

Suspect the code path that receives blocks from EL peers isn't writing withdrawals to disk

Signed-off-by: Simon Dudley <simon.dudley@consensys.net>

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/core/Block.java

@@ -62,6 +62,8 @@ public void writeTo(final RLPOutput out) {
     out.writeList(body.getTransactions(), Transaction::writeTo);
     out.writeList(body.getOmmers(), BlockHeader::writeTo);
 
+    body.getWithdrawals().ifPresent(withdrawals -> out.writeList(withdrawals, Withdrawal::writeTo));
+
     out.endList();
   }