Abort is triggered in debug build due to logical error.

```
CREATE TABLE A(k UInt32, t UInt32, a UInt64) ENGINE = MergeTree() ORDER BY (k, t);
INSERT INTO A(k,t,a) VALUES (1,101,1),(1,102,2),(1,103,3),(1,104,4),(1,105,5);

CREATE TABLE B(k UInt32, t UInt32, b UInt64) ENGINE = MergeTree() ORDER BY (k, t);
INSERT INTO B(k,t,b) VALUES (1,102,2), (1,104,4);

SELECT 
    (257, NULL, NULL), 
    (1, -2), 
    (-2, 7), 
    ('102.5', '0.03', NULL, NULL, NULL), 
    A.k, 
    toString((10, 0), 10.000100135803223), 
    A.a, 
    B.b, 
    toString(B.t), 
    B.k
FROM A
ASOF INNER JOIN B ON (A.k = B.k) AND NULL AND greaterOrEquals(B.t)
ORDER BY tuple(A.k) ASC;


Received exception from server (version 20.7.1):
Code: 1001. DB::Exception: Received from localhost:9000. DB::Exception: St12out_of_range: vector. 
```

{
        if (auto * func = ast->as<ASTFunction>())
            visit(*func, ast, data);
    }
    static bool needChildVisit(const ASTPtr & node, const ASTPtr &)
    {
        if (auto * func = node->as<ASTFunction>())
            if (func->name == "equals")
                return false;
        return true;
    }
private:
    static void visit(const ASTFunction & func, const ASTPtr & ast, Data & data);
    static void getIdentifiers(const ASTPtr & ast, std::vector<const ASTIdentifier *> & out);
    static std::pair<size_t, size_t> getTableNumbers(const ASTPtr & expr, const ASTPtr & left_ast, const ASTPtr & right_ast, Data & data);
    static const ASTIdentifier * unrollAliases(const ASTIdentifier * identifier, const Aliases & aliases);
    static size_t getTableForIdentifiers(std::vector<const ASTIdentifier *> & identifiers, const Data & data);
    [[noreturn]] static void throwSyntaxException(const String & msg);
};
using CollectJoinOnKeysVisitor = CollectJoinOnKeysMatcher::Visitor;
}