Upgrade build tools (#2575)

* Upgrade webpack

* Upgrade babel

* Upgrade build tools

* Add missing dependency

package.json

@@ -131,8 +131,6 @@
     "merge-stream": "^1.0.1",
     "mocha": "^5.2.0",
     "parse5": "^5.1.0",
-    "polymer-analyzer": "^3.1.2",
-    "polymer-bundler": "^4.0.2",
     "polymer-cli": "^1.8.0",
     "prettier": "^1.14.3",
     "raw-loader": "^0.5.1",
@@ -145,6 +143,7 @@
     "tslint-eslint-rules": "^5.4.0",
     "tslint-plugin-prettier": "^2.0.1",
     "typescript": "^3.1.4",
+    "uglifyjs-webpack-plugin": "^2.1.1",
     "wct-browser-legacy": "^1.0.1",
     "web-component-tester": "^6.8.0",
     "webpack": "^4.19.1",