Performance of ORDER BY on sorting key prefix with braces is 2x slower than without due to inefficient execution plan.
Without braces:
```sql
EXPLAIN PIPELINE
SELECT
    CounterID,
    EventDate
FROM hits_v1
ORDER BY
    CounterID ASC,
    EventDate ASC

┌─explain───────────────────────────┐
│ (Expression)                      │
│ ExpressionTransform               │
│   (Sorting)                       │
│   MergingSortedTransform 19 → 1   │
│     (Expression)                  │
│     ExpressionTransform × 19      │
│       (ReadFromMergeTree)         │
│       MergeTreeInOrder × 19 0 → 1 │
└───────────────────────────────────┘
```
With braces:
```sql
EXPLAIN PIPELINE
SELECT
    CounterID,
    EventDate
FROM hits_v1
ORDER BY (CounterID, EventDate) ASC

┌─explain────────────────────────────────┐
│ (Expression)                           │
│ ExpressionTransform                    │
│   (Sorting)                            │
│   MergingSortedTransform 16 → 1        │
│     MergeSortingTransform × 16         │
│       LimitsCheckingTransform × 16     │
│         PartialSortingTransform × 16   │
│           (Expression)                 │
│           ExpressionTransform × 16     │
│             (ReadFromMergeTree)        │
│             MergeTreeThread × 16 0 → 1 │
└────────────────────────────────────────┘
```
{
        
        return typeid_cast<ASTTableJoin  *>(parent.get()) == nullptr;
    }
    static void visit(ASTPtr & ast, Data &)
    {
        if (auto * identifier = typeid_cast<ASTIdentifier *>(ast.get()))
            visit(*identifier, ast);
    }
    static void visit(ASTIdentifier & identifier, ASTPtr & ast)
    {
        if (identifier.shortName() != "_shard_num")
            return;
        String alias = identifier.tryGetAlias();
        if (alias.empty())
            alias = "_shard_num";
        ast = makeASTFunction("shardNum");
        ast->setAlias(alias);
    }
};
using RewriteShardNumVisitor = InDepthNodeVisitor<RewriteShardNum, true>;
}
TreeRewriterResult::TreeRewriterResult(