Fix query planning for complex queries with impossible conditions.

[arthurschreiber]

Description

This fixes the issue described in #18987, but using a different / more generic approach compared to #19002.

First, this changes *SemTable.CopySemanticInfo to only copy type information, and only copy dependency information when copying from sqlparser.Expr to sqlparser.ColName.

This also fixes another issue where the correlation logic for subqueries was incorrect and we'd end up marking too many subqueries correlated even though in fact they were not correlated. This was previously hidden by the dependency information copy that happened in *SemTable.CopySemanticInfo.

Related Issue(s)

See #19002 and #18987

Checklist

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[arthurschreiber]

Note to self: fix the indentation here.

[arthurschreiber]

All ANDed conditions are now correctly replaced by 0, and the final route variant is None.

[andyedison]

I cherry picked this fix into my fork reproducing our bug in #18987 and confirmed that it does the expected Variant: None

"Inputs": [
    {
    "InputName": "SubQuery",
    "OperatorType": "Limit",
    "Count": "100",
    "Offset": "0",
    "Inputs": [
        {
        "OperatorType": "Route",
        "Variant": "None",
        "Keyspace": {
            "Name": "foobar_ks",
            "Sharded": true
        },
        "FieldQuery": "select id, subquery_for_limit.updated_at from (select foobar.id, foobar.updated_at from foobar where 1 != 1) as subquery_for_limit where 1 != 1",
        "OrderBy": "1 DESC",
        "Query": "select id, subquery_for_limit.updated_at from (select foobar.id, foobar.updated_at from foobar where 0) as subquery_for_limit order by subquery_for_limit.updated_at desc limit 100"
        }
    ]
    },
]