revert: "fix: window.open site instance should belong to same browsing instance (#15216)" (#15757)

This reverts commit 8f35198bfb.

spec/fixtures/module/preload-sandbox.js

@@ -22,16 +22,7 @@
     }
   } else if (location.href !== 'about:blank') {
     addEventListener('DOMContentLoaded', () => {
-      ipcRenderer.on('touch-the-opener', () => {
-        let errorMessage = null
-        try {
-          const openerDoc = opener.document // eslint-disable-line no-unused-vars
-        } catch (error) {
-          errorMessage = error.message
-        }
-        ipcRenderer.send('answer', errorMessage)
-      })
       ipcRenderer.send('child-loaded', window.opener == null, document.body.innerHTML, location.href)
-    })
+    }, false)
   }
 })()