fixup! TF-4224 Reduce ReDoS vulnerability

core/test/utils/redos_vulnerability_test.dart

@@ -361,23 +361,9 @@ void main() {
     group('Regex initialization optimization', () {
       test('regex patterns should be reused, not recreated', () {
         // This test verifies that regex patterns are static and reused
-        // We can't directly test if they're the same object, but we can
-        // verify performance doesn't degrade with multiple calls
-
-        const iterations = 1000;
-        final stopwatch = Stopwatch()..start();
-
-        for (var i = 0; i < iterations; i++) {
-          StringConvert.isTextTable('| a | b |\n|---|---|\n| c | d |');
-          HtmlUtils.wrapPlainTextLinks('<p>https://example.com</p>');
-          StringConvert.extractEmailAddress('test@example.com, test2@example.com');
-        }
-
-        stopwatch.stop();
-
-        // If regex patterns were being recreated each time, this would be much slower
-        expect(stopwatch.elapsedMilliseconds, lessThan(500),
-            reason: 'Multiple calls should be fast due to regex reuse');
+        final regex1 = StringConvert.base64ValidationRegex;
+        final regex2 = StringConvert.base64ValidationRegex;
+        expect(identical(regex1, regex2), true);
       });
     });
   });