Upgrade sane and use FSEventsWatcher on Darwin (#3918)

This is to fix regressions with the NodeWatcher on macOS.
More info here: amasad/sane#97

Author: SimenB

packages/jest-haste-map/package.json

@@ -12,7 +12,7 @@
     "graceful-fs": "^4.1.11",
     "jest-docblock": "^20.0.3",
     "micromatch": "^2.3.11",
-    "sane": "~1.6.0",
+    "sane": "^2.0.0",
     "worker-farm": "^1.3.1"
   }
 }

packages/jest-haste-map/src/index.js

@@ -568,7 +568,7 @@ class HasteMap extends EventEmitter {
 
     const Watcher = canUseWatchman && this._options.useWatchman
       ? sane.WatchmanWatcher
-      : sane.NodeWatcher;
+      : os.platform() === 'darwin' ? sane.FSEventsWatcher : sane.NodeWatcher;
     const extensions = this._options.extensions;
     const ignorePattern = this._options.ignorePattern;
     let changeQueue = Promise.resolve();