modify minimizer option of TerserPlugin

Signed-off-by: ctw <chentingwei2@huawei.com>
Change-Id: Ic870dc3416c90351b8d81a4a1bf9200144a9a8f8

compiler/webpack.config.js

@@ -146,7 +146,13 @@ function setReleaseConfig(config) {
     emitOnErrors: true,
     usedExports: false,
     minimize: true,
-    minimizer: [new TerserPlugin()]
+    minimizer: [new TerserPlugin({
+      terserOptions: {
+        compress: {
+          join_vars: false
+        }
+      }
+    })]
   };
   config.output.sourceMapFilename = '_releaseMap/[name].js.map';
 }