Convert one small utility to verify the build works

Author: dfreeman

ts/lib/utilities/tmpdir.js

@@ -0,0 +1,7 @@
+'use strict';
+
+import * as os from 'os';
+import * as fs from 'fs';
+
+// Watchman gets upset when it receives non-canonical paths as watch roots
+export = () => fs.realpathSync(os.tmpdir());