Store the async-await compiled pub code directly in the repo.

sdk/lib/_internal/pub_generated/test/dart2js/ignores_entrypoint_in_dependency_test.dart

+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+import '../serve/utils.dart';
+main() {
+  initConfig();
+  integration("ignores a Dart entrypoint in a dependency", () {
+    d.dir(
+        "foo",
+        [
+            d.libPubspec("foo", "0.0.1"),
+            d.dir("lib", [d.file("lib.dart", "main() => print('foo');")])]).create();
+    d.dir(appPath, [d.appPubspec({
+        "foo": {
+          "path": "../foo"
+        }
+      })]).create();
+    pubServe(shouldGetFirst: true);
+    requestShould404("web/packages/foo/lib.dart.js");
+    endPubServe();
+  });
+}