While working on the other patch [1] that touched tbm_add_tuples() under src/backend/nodes, I moved a loop variable into for statement by the way as I knew Peter Eisentraut had done some efforts about that, see [2].
However, Peter removed that change from the patch and he said that should belong to a separate cleanup patch. So I am following up and moving loop variables into for statements wherever possible under src/backend/nodes.
