panic in write_final_status_line with on-timeout = pass

nextest panics when using `on-timeout = "pass"`: ``` internal error: entered unreachable code: success is limited to pass and leak, found Timeout { result: Pass } ``` config to repro: ```toml [[profile.default.overrides]] filter = "test(slow_test)" slow-timeout = { period = "60s", terminate-after = 4, on-timeout = "pass" } ``` `write_final_status_line` and `output_spec_for_finished` don't handle `Timeout { Pass }` fix: #2940