Add white-listing to sourcemap tests.

tests/compiler/dart2js/sourcemaps/source_mapping_operators_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'source_mapping_tester.dart' as tester;
+import 'source_mapping_tester.dart';
+import 'sourcemap_helper.dart';
+import 'package:compiler/src/io/position_information.dart';
 
 void main() {
-  tester.main(['operators']);
+  test(['operators'], whiteListFunction: (String config, String file) {
+    bool allowGtOptimization(CodePoint codePoint) {
+      // Allow missing code points for bailout optimization.
+      return codePoint.jsCode.contains(r'.$gt()'); // # Issue 25304
+    }
+
+    if (config == 'cps') {
+      return (CodePoint codePoint) {
+        // Temporarily allow missing code points on expression statements.
+        if (codePoint.kind == StepKind.EXPRESSION_STATEMENT ||
+            codePoint.kind == StepKind.IF_CONDITION) {
+          return true;
+        }
+        if (codePoint.jsCode.contains(r'H.iae(')) {
+          // Allow missing code points for bailout calls.
+          return true;
+        }
+        return allowGtOptimization(codePoint);
+      };
+    }
+    return allowGtOptimization;
+  });
 }