Fix double lookup failure on ESQL

[jackpan123]

Fix double lookup failure on ESQL (Closes #111398 ).
I also try three times LOOKUP, it is fine, result like below:

 curl -XPOST "http://localhost:9200/_query?format=txt" -H "kbn-xsrf: reporting" -H "Content-Type: application/json" -d' ─╯ { "query": "from test | lookup test2 on foo | lookup test3 on foo | lookup test4 on foo", "tables": { "test2": { "foo": {"keyword": ["bar"]}, "field21": {"long": [123]}, "field22": {"long": [123]} }, "test3": { "foo": {"keyword": ["bar"]}, "field31": {"long": [5]}, "field32": {"long": [5]} }, "test4": { "foo": {"keyword": ["bar"]}, "field41": {"long": [6]}, "field42": {"long": [6]} } } }' field11 | field12 | foo | field21 | field22 | field31 | field32 | field41 | field42 ---------------+---------------+---------------+---------------+---------------+---------------+---------------+---------------+--------------- 123 |5 |bar |123 |123 |5 |5 |6 |6 123 |5 |bar |123 |123 |5 |5 |6 |6 

[jackpan123]

Can someone help me assign some labels?

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[alex-spies]

Thanks a lot for your contribution, @jackpan123, nice find!

The fix looks good to me. We will not be able to close #111398 with this, though. Because we'd have to add tests to avoid regressions in the future - but more importantly because LOOKUP is still under development and currently changing a lot, so that the corresponding tests are disabled right now.

[alex-spies]

@elasticsearchmachine test this please

[alex-spies]

@elasticsearchmachine generate changelog

[alex-spies]

@elasticsearchmachine test this please

[elasticsearchmachine]

💚 Backport successful

Status	Branch	Result
✅	8.x