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

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

+import 'package:path/path.dart' as path;
+import 'package:scheduled_test/scheduled_test.dart';
+import 'package:unittest/unittest.dart';
+import '../../../lib/src/lock_file.dart';
+import '../../../lib/src/source_registry.dart';
+import '../../descriptor.dart' as d;
+import '../../test_pub.dart';
+main() {
+  initConfig();
+  integration("can use relative path", () {
+    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(
+        packagesPath,
+        [d.dir("foo", [d.file("foo.dart", 'main() => "foo";')])]).validate();
+  });
+  integration("path is relative to containing d.pubspec", () {
+    d.dir(
+        "relative",
+        [d.dir("foo", [d.libDir("foo"), d.libPubspec("foo", "0.0.1", deps: {
+          "bar": {
+            "path": "../bar"
+          }
+        })]),
+            d.dir("bar", [d.libDir("bar"), d.libPubspec("bar", "0.0.1")])]).create();
+    d.dir(appPath, [d.appPubspec({
+        "foo": {
+          "path": "../relative/foo"
+        }
+      })]).create();
+    pubGet();
+    d.dir(
+        packagesPath,
+        [
+            d.dir("foo", [d.file("foo.dart", 'main() => "foo";')]),
+            d.dir("bar", [d.file("bar.dart", 'main() => "bar";')])]).validate();
+  });
+  integration("relative path preserved in the lockfile", () {
+    d.dir("foo", [d.libDir("foo"), d.libPubspec("foo", "0.0.1")]).create();
+    d.dir(appPath, [d.appPubspec({
+        "foo": {
+          "path": "../foo"
+        }
+      })]).create();
+    pubGet();
+    schedule(() {
+      var lockfilePath = path.join(sandboxDir, appPath, "pubspec.lock");
+      var lockfile = new LockFile.load(lockfilePath, new SourceRegistry());
+      var description = lockfile.packages["foo"].description;
+      expect(path.isRelative(description["path"]), isTrue);
+    });
+  });
+}