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

sdk/lib/_internal/pub_generated/test/transformer/exclusion/exclude_asset_string_test.dart

Index: sdk/lib/_internal/pub_generated/test/transformer/exclusion/exclude_asset_string_test.dart
diff --git a/sdk/lib/_internal/pub_generated/test/transformer/exclusion/exclude_asset_string_test.dart b/sdk/lib/_internal/pub_generated/test/transformer/exclusion/exclude_asset_string_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..9ea2bf6ab381745579765d0d9d07339f10ff318e
--- /dev/null
+++ b/sdk/lib/_internal/pub_generated/test/transformer/exclusion/exclude_asset_string_test.dart
@@ -0,0 +1,32 @@
+library pub_tests;
+import '../../descriptor.dart' as d;
+import '../../test_pub.dart';
+import '../../serve/utils.dart';
+main() {
+  initConfig();
+  withBarbackVersions("any", () {
+    integration("allows a single string as the asset to exclude", () {
+      d.dir(appPath, [d.pubspec({
+          "name": "myapp",
+          "transformers": [{
+              "myapp/src/transformer": {
+                "\$exclude": "web/foo.txt"
+              }
+            }]
+        }),
+            d.dir("lib", [d.dir("src", [d.file("transformer.dart", REWRITE_TRANSFORMER)])]),
+            d.dir(
+                "web",
+                [
+                    d.file("foo.txt", "foo"),
+                    d.file("bar.txt", "bar"),
+                    d.dir("sub", [d.file("foo.txt", "foo")])])]).create();
+      createLockFile('myapp', pkg: ['barback']);
+      pubServe();
+      requestShould404("foo.out");
+      requestShouldSucceed("sub/foo.out", "foo.out");
+      requestShouldSucceed("bar.out", "bar.out");
+      endPubServe();
+    });
+  });
+}