Add test for jumping shards

[mhchia]

Besides,

• Don't print blobs in collation to avoid unnecessary output.
• Fix port and rpcport, no matter what seed is used.
  • port and rpcport can be changed by specifying them when starting a node. To call RPC to the node, rpcport should be specified.
  • Accordingly, addpeer ip seed is changed to addpeer ip port seed. The example usage can be found in cli-example/setup-3-partial-connecting-nodes.sh

[mhchia]

cc @ChihChengLiang