The fused node carried the PromQL text it was compiled from and printed it
on its EXPLAIN line, so a split aggregate's two halves - the frontend's
final tree and the region's partial prefix - showed the same statement over
different plans. Both halves now print their own tree: the logical node
without figures, the physical node with each tree node's metrics. The query
text is gone from the node, its payload and its identity.
Signed-off-by: discord9 <discord9@163.com>