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

sdk/lib/_internal/pub_generated/test/get/path/relative_symlink_test.dart

+import 'dart:io';
+import 'package:path/path.dart' as path;
+import '../../descriptor.dart' as d;
+import '../../test_pub.dart';
+main() {
+  if (Platform.operatingSystem == "windows") return;
+  initConfig();
+  integration(
+      "generates a symlink with a relative path if the dependency "
+          "path was relative",
+      () {
+    d.dir("foo", [d.libDir("foo"), d.libPubspec("foo", "0.0.1")]).create();
+    d.dir(appPath, [d.appPubspec({
+        "foo": {
+          "path": "../foo"
+        }
+      })]).create();
+    pubGet();
+    d.dir("moved").create();
+    scheduleRename("foo", path.join("moved", "foo"));
+    scheduleRename(appPath, path.join("moved", appPath));
+    d.dir(
+        "moved",
+        [
+            d.dir(
+                packagesPath,
+                [d.dir("foo", [d.file("foo.dart", 'main() => "foo";')])])]).validate();
+  });
+}