Teach analyzer parser to handle native const factories/const constructors.

pkg/analyzer/test/generated/non_error_resolver_test.dart

Index: pkg/analyzer/test/generated/non_error_resolver_test.dart
diff --git a/pkg/analyzer/test/generated/non_error_resolver_test.dart b/pkg/analyzer/test/generated/non_error_resolver_test.dart
index fd4487f6e961b8856a82a6163730f8c8e4fe13a0..f172ec6ed1146c987ca34851215464c1c1a2da44 100644
--- a/pkg/analyzer/test/generated/non_error_resolver_test.dart
+++ b/pkg/analyzer/test/generated/non_error_resolver_test.dart
@@ -3727,6 +3727,18 @@ int m(a) native 'string';''');
     // Cannot verify the AST because the import's URI cannot be resolved.
   }
 
+  void test_nativeConstConstructor() {
+    Source source = addSource(r'''
+import 'dart-ext:x';
+class Foo {
+  const Foo() native 'Foo_Foo';
+  const factory Foo.foo() native 'Foo_Foo_foo';
+}''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    // Cannot verify the AST because the import's URI cannot be resolved.
+  }
+
   void test_newWithAbstractClass_factory() {
     Source source = addSource(r'''
 abstract class A {