Don’t set env to production for testing

playground and other test builds (e.g. blocks-only) are only in develop now.

package.json

@@ -9,7 +9,7 @@
     "deploy": "touch build/.nojekyll && gh-pages -t -d build -m \"Build for $(git log --pretty=format:%H -n1)\"",
     "i18n:src": "babel src > tmp.js && rimraf tmp.js && build-i18n-src ./translations/messages/ ./translations/",
     "start": "webpack-dev-server",
-    "test": "npm run test:lint && npm run test:unit && NODE_ENV=production npm run build && npm run test:integration",
+    "test": "npm run test:lint && npm run test:unit && npm run build && npm run test:integration",
     "test:integration": "jest --runInBand test[\\\\/]integration",
     "test:lint": "eslint . --ext .js,.jsx",
     "test:unit": "jest test[\\\\/]unit",