Remove Babel plugin for ES Modules (#2975)

* Remove Babel plugin for ES Modules

Processing of ES Modules is executed by Webpack.
Don't have to do it on Babel side.

* Add plugin for test

.babelrc

@@ -5,6 +5,7 @@
       "env",
       {
         "loose": true,
+        "modules": false,
         "targets": {
           "browsers": ["last 2 versions", "IE >= 11", "iOS >= 9"]
         }
@@ -33,6 +34,11 @@
       "plugins": [
         "lodash"
       ]
+    },
+    "test": {
+      "plugins": [
+        "transform-es2015-modules-commonjs"
+      ]
     }
   }
 }

package.json

@@ -10,7 +10,7 @@
     "storybook": "start-storybook -p 9001 -c storybook",
     "test": "npm run test:lint && npm run test:mocha",
     "test:lint": "eslint -c .eslintrc.yml --ext=js --ext=jsx app/javascript/",
-    "test:mocha": "mocha --require ./spec/javascript/setup.js --compilers js:babel-register ./spec/javascript/components/*.test.jsx",
+    "test:mocha": "NODE_ENV=test mocha --require ./spec/javascript/setup.js --compilers js:babel-register ./spec/javascript/components/*.test.jsx",
     "postinstall": "npm rebuild node-sass"
   },
   "repository": {
@@ -29,6 +29,7 @@
     "babel-plugin-react-transform": "^2.0.2",
     "babel-plugin-syntax-dynamic-import": "^6.18.0",
     "babel-plugin-transform-class-properties": "^6.24.1",
+    "babel-plugin-transform-es2015-modules-commonjs": "^6.24.1",
     "babel-plugin-transform-object-rest-spread": "^6.23.0",
     "babel-plugin-transform-react-jsx-self": "^6.22.0",
     "babel-plugin-transform-react-jsx-source": "^6.22.0",

yarn.lock

@@ -718,16 +718,7 @@ babel-plugin-transform-class-properties@6.16.0:
     babel-plugin-syntax-class-properties "^6.8.0"
     babel-runtime "^6.9.1"
 
-babel-plugin-transform-class-properties@^6.22.0:
-  version "6.22.0"
-  resolved "https://registry.yarnpkg.com/babel-plugin-transform-class-properties/-/babel-plugin-transform-class-properties-6.22.0.tgz#aa78f8134495c7de06c097118ba061844e1dc1d8"
-  dependencies:
-    babel-helper-function-name "^6.22.0"
-    babel-plugin-syntax-class-properties "^6.8.0"
-    babel-runtime "^6.22.0"
-    babel-template "^6.22.0"
-
-babel-plugin-transform-class-properties@^6.24.1:
+babel-plugin-transform-class-properties@^6.22.0, babel-plugin-transform-class-properties@^6.24.1:
   version "6.24.1"
   resolved "https://registry.yarnpkg.com/babel-plugin-transform-class-properties/-/babel-plugin-transform-class-properties-6.24.1.tgz#6a79763ea61d33d36f37b611aa9def81a81b46ac"
   dependencies: