Handle synthetic nodes use to throw exceptions

tests/compiler/dart2js/mock_libraries.dart

Index: tests/compiler/dart2js/mock_libraries.dart
diff --git a/tests/compiler/dart2js/mock_libraries.dart b/tests/compiler/dart2js/mock_libraries.dart
index 867bf4d37667db8cb4d99606e024461e5afbf6f0..501e0dcd4cf3572bfa472a643437084f6ae775d6 100644
--- a/tests/compiler/dart2js/mock_libraries.dart
+++ b/tests/compiler/dart2js/mock_libraries.dart
@@ -101,6 +101,10 @@ const Map<String, String> DEFAULT_CORE_LIBRARY = const <String, String>{
   'Symbol': 'class Symbol { final name; const Symbol(this.name); }',
   'Type': 'class Type {}',
   'Pattern': 'abstract class Pattern {}',
+
+  '_genericNoSuchMethod': '_genericNoSuchMethod(a,b,c,d,e) {}',
+  '_unresolvedConstructorError': '_unresolvedConstructorError(a,b,c,d,e) {}',
+  '_malformedTypeError': '_malformedTypeError(message) {}',
 };
 
 const String DEFAULT_PATCH_CORE_SOURCE = r'''