### _Why are the changes needed?_
For the operation getNextRowSet method, we shall add lock for it.
For example, for spark operation, the result iterator is not thread-safe, it might throw exception(if the jdbc client to kyuubi server connection socket timeout).
For incremental collect mode, the fetchResult might trigger a spark task to collect the incremental result(`self.next().toIterator`).
The jdbc client to kyuubi gateway timeout, but the fetchResult request has been sent to engine.
Then the jdbc client re-send the fetchResult request.
And the getNextResultSet in spark engine side concurrent execute.
And the result iterator is not thread-safe and might cause NPE.
### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible
- [ ] Add screenshots for manual tests if appropriate
- [x] [Run test](https://kyuubi.readthedocs.io/en/master/develop_tools/testing.html#running-tests) locally before make a pull request
Closes#4949 from turboFei/lock_next_rowset.
Closes#4949
8f18f3236 [fwang12] getNextRowSetInternal and withLockRequired
Authored-by: fwang12 <fwang12@ebay.com>
Signed-off-by: fwang12 <fwang12@ebay.com>
7d8e89c27f