Refactor <webview> tag tests (#12886)

spec/fixtures/module/preload-required-module.js

@@ -1,5 +1,12 @@
 try {
-  console.log([typeof process, typeof setImmediate, typeof global, typeof Buffer, typeof global.Buffer].join(' '))
+  const types = {
+    process: typeof process,
+    setImmediate: typeof setImmediate,
+    global: typeof global,
+    Buffer: typeof Buffer,
+    'global.Buffer': typeof global.Buffer
+  }
+  console.log(JSON.stringify(types))
 } catch (e) {
   console.log(e.message)
 }