HashJoinExec.Close should wait for the exit of innerWorker

[XuHuaiyu]

After, #6856 the inner data fetcher and outer data fetcher will run
simultaneously. If an error happens during fetching the outer table data,
HashJoinExec.Close will be called, but the inner data fetcher may be still
running at this time. Some unexpected error may be raised due to this such
as data race. So, the inner data fetcher should exit in time if there is an
error found in outer data fetcher, and HashJoinExec.Close should wait for
the exit of inner data fetcher.

[XuHuaiyu]

Fix in #7554