WebUI: Roll uglify-es to version 3.3.9.

This rolls uglify-es to a version that has async/await support.

Bug: 905927
Change-Id: I76ff7048a42c5915534bdcd43549460a713ea886
Reviewed-on: https://chromium-review.googlesource.com/c/1339085
Commit-Queue: calamity <calamity@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609168}

third_party/node/node_modules.tar.gz.sha1

-dc855853e383fc88c56845f772c259f25a3ed045
+c0e0f34498afb3f363cc37cd2e9c1a020cb020d9

third_party/node/package.json

@@ -7,6 +7,6 @@
     "eslint": "3.19.0",
     "polymer-bundler": "3.1.1",
     "polymer-css-build": "0.3.3",
-    "uglify-es": "3.0.15"
+    "uglify-es": "3.3.9"
   }
 }