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

sdk/lib/_internal/pub_generated/test/serve/gets_first_if_git_ref_changed_test.dart

+library pub_tests;
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+import 'utils.dart';
+main() {
+  initConfig();
+  integration(
+      "gets first if a git dependency's ref doesn't match the one in "
+          "the lock file",
+      () {
+    var repo =
+        d.git('foo.git', [d.libDir('foo', 'before'), d.libPubspec('foo', '1.0.0')]);
+    repo.create();
+    var commit1 = repo.revParse('HEAD');
+    d.git(
+        'foo.git',
+        [d.libDir('foo', 'after'), d.libPubspec('foo', '1.0.0')]).commit();
+    var commit2 = repo.revParse('HEAD');
+    d.appDir({
+      "foo": {
+        "git": {
+          "url": "../foo.git",
+          "ref": commit1
+        }
+      }
+    }).create();
+    pubGet();
+    d.appDir({
+      "foo": {
+        "git": {
+          "url": "../foo.git",
+          "ref": commit2
+        }
+      }
+    }).create();
+    pubServe(shouldGetFirst: true);
+    requestShouldSucceed("packages/foo/foo.dart", 'main() => "after";');
+    endPubServe();
+  });
+}