util: fix inspecting URL subclass prototypes

Check the URL private field brand before accessing href to avoid
throwing when inspecting URL subclass prototypes.

Assisted-by:Codex:6.1SolHigh
Signed-off-by: HoonDongKang <d159123@naver.com>

Author: HoonDongKang

lib/internal/util/inspect.js

@@ -205,7 +205,7 @@ function pathToFileUrlHref(filepath) {
 
 function isURL(value) {
   internalUrl ??= require('internal/url');
-  return typeof value.href === 'string' && value instanceof internalUrl.URL;
+  return internalUrl.isURLInstance(value) && typeof value.href === 'string';
 }
 
 const builtInObjects = new SafeSet(

test/parallel/test-util-inspect-url.js

@@ -0,0 +1,35 @@
+'use strict';
+
+require('../common');
+const assert = require('assert');
+const { format, inspect } = require('util');
+
+class TestURL extends URL {}
+
+assert.strictEqual(inspect(TestURL.prototype), 'URL {}');
+assert.strictEqual(
+  inspect(TestURL.prototype, { customInspect: false }),
+  'URL {}',
+);
+
+// Inspecting hidden properties must not throw when reaching the prototype.
+inspect(TestURL, { showHidden: true });
+inspect({ TestURL }, { showHidden: true });
+format('%o', { TestURL });
+
+const url = new TestURL('https://example.org/');
+assert.strictEqual(
+  inspect(url, { customInspect: false }),
+  'https://example.org/',
+);
+
+class NonStringURL extends URL {
+  get href() {
+    return undefined;
+  }
+}
+
+assert.strictEqual(
+  inspect(new NonStringURL('https://example.org/'), { customInspect: false }),
+  'NonStringURL [URL] {}',
+);