[CFE] Forgotten test for external fields and advanced invalidation fix

This CL is a test I forgot to include in
https://dart-review.googlesource.com/c/sdk/+/188461
even though I wrote it and used it to verify the fix.
Better late than never.

Change-Id: I6371719ce0d447f6ef9aeb6ebed2b7615c911b6d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/190480
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Jens Johansen <[email protected]>

Author: jensjoha

pkg/front_end/testcases/incremental/no_outline_change_46.yaml

@@ -0,0 +1,27 @@
+# Copyright (c) 2021, 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.md file.
+
+# Reproduce a crash.
+
+type: newworld
+target: VM
+worlds:
+  - entry: main.dart
+    experiments: alternative-invalidation-strategy,non-nullable
+    sources:
+      main.dart: |
+        class Foo {
+          external int x;
+        }
+    expectedLibraryCount: 1
+
+  - entry: main.dart
+    experiments: alternative-invalidation-strategy,non-nullable
+    worldType: updated
+    expectInitializeFromDill: false
+    invalidate:
+      - main.dart
+    expectedLibraryCount: 1
+    expectsRebuildBodiesOnly: true
+

pkg/front_end/testcases/incremental/no_outline_change_46.yaml.world.1.expect

@@ -0,0 +1,11 @@
+main = <No Member>;
+library from "org-dartlang-test:///main.dart" as main {
+
+  class Foo extends dart.core::Object {
+    synthetic constructor •() → main::Foo
+      : super dart.core::Object::•()
+      ;
+    external get x() → dart.core::int;
+    external set x(dart.core::int #externalFieldValue) → void;
+  }
+}

pkg/front_end/testcases/incremental/no_outline_change_46.yaml.world.2.expect

@@ -0,0 +1,11 @@
+main = <No Member>;
+library from "org-dartlang-test:///main.dart" as main {
+
+  class Foo extends dart.core::Object {
+    synthetic constructor •() → main::Foo
+      : super dart.core::Object::•()
+      ;
+    external get x() → dart.core::int;
+    external set x(dart.core::int #externalFieldValue) → void;
+  }
+}