Implement fs.stat and fs.readlink

Summary: Fixes issue for the stackTraceMapper

Reviewed By: aigoncharov

Differential Revision: D32987161

fbshipit-source-id: 660f49a1bdf61b2fd2963874ef23dfd284f71128

desktop/flipper-ui-core/src/utils/flipperLibImplementation/index.tsx

@@ -111,6 +111,10 @@ export function initializeFlipperLibImplementation(
             flags,
           ),
         constants: fsConstants,
+        stat: async (path: string) =>
+          renderHost.flipperServer.exec('node-api-fs-stat', path),
+        readlink: async (path: string) =>
+          renderHost.flipperServer.exec('node-api-fs-readlink', path),
       },
       downloadFile: downloadFileFactory(renderHost),
     },