Fix flaky test in watcher.rs
Fix flaky test in watcher.rs

- fixes #618

fuchsia-mirror/third_party-xi-editor,fuchsia-mirror/third_party-xi-editor,google/xi-editor,fuchsia-mirror/third_party-xi-editor,google/xi-editor,fuchsia-mirror/third_party-xi-editor,google/xi-editor,google/xi-editor