History of scheduler 2 changes

In crates/hub/src/flow.rs, lines 2393–2407 on cancel-landed-runs. Every change that wrote or deleted one of these lines, or deleted a line from between them. Exact, because each line keeps its identity across edits; edits elsewhere in the file are not here. Also: oxy log -L 2393,2407:crates/hub/src/flow.rs.