Merge branch 'diff-worker-js-fix' into 'master'

Fixed diff_worker not compiling correctly

Closes #41182

See merge request gitlab-org/gitlab-ce!15966

config/webpack.config.js

@@ -118,7 +118,10 @@ var config = {
       },
       {
         test: /\_worker\.js$/,
-        loader: 'worker-loader',
+        use: [
+          { loader: 'worker-loader' },
+          { loader: 'babel-loader' },
+        ],
       },
       {
         test: /\.(worker(\.min)?\.js|pdf|bmpr)$/,