test-browser: work around weird webkit behaviour (#8802)

Author: alxndrsn

bin/test-browser.js

@@ -161,6 +161,15 @@ async function startTest() {
   const page = await browser.newPage();
 
   page.on('pageerror', err => {
+    if (browserName === 'webkit' && err.toString()
+        .match(/^Fetch API cannot load http.* due to access control checks.$/)) {
+      // This is an _uncatchable_, error seen in playwright v1.36.1 webkit. If
+      // it is ignored, fetch() will also throw a _catchable_:
+      // `TypeError: Load failed`
+      console.log('Ignoring error:', err);
+      return;
+    }
+
     console.log('Unhandled error in test page:', err);
     process.exit(1);
   });