Ensure that Motion nodes under HashJoin with outer refers are not rescanned

[wuyuhao28]

Previously (#6776) we fix plans with a Nested Loop join on the inner side of another Nested Loop join, executor may produce an error:

ERROR: illegal rescan of motion node: invalid plan HINT: Likely caused by bad NL-join, try setting enable_nestloop to off

But this error will happen with Hash Join plan, this commit adds a shield material node on the required Hash Join outer side.