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