[class] test extending class expression without private methods

Address a TODO in tests

Bug: v8:8330
Change-Id: I2b8d5cef488ca56331448dcb11fad7a00f19d501
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2095638Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Cr-Commit-Position: refs/heads/master@{#66693}

test/mjsunit/harmony/private-methods.js

@@ -266,8 +266,10 @@
 }
 
 {
-  // TODO(v8:9177): test extending a class expression that does not have
-  // a private method.
+  class A extends class { } {
+    #a() {}
+  }
+
   class D extends class {
     #c() {}
   } {
@@ -278,6 +280,7 @@
     #e() {}
   }
 
+  new A;
   new D;
   new E;
 }