History of JobGroup::drop 1 change

In crates/flow/src/syscall.rs, lines 428–437 on c8917cf1f9310b5fbb0f6a44f016b6b956ab702b689992917cade6ceac375d65. 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 428,437:crates/flow/src/syscall.rs.