Revert "Use native async/await support in pub."

sdk/lib/_internal/pub_generated/test/snapshot/upgrades_snapshot_test.dart

Index: sdk/lib/_internal/pub_generated/test/snapshot/upgrades_snapshot_test.dart
diff --git a/sdk/lib/_internal/pub/test/snapshot/upgrades_snapshot_test.dart b/sdk/lib/_internal/pub_generated/test/snapshot/upgrades_snapshot_test.dart
similarity index 54%
copy from sdk/lib/_internal/pub/test/snapshot/upgrades_snapshot_test.dart
copy to sdk/lib/_internal/pub_generated/test/snapshot/upgrades_snapshot_test.dart
index 10aefb6bbb2024f0bb5d5ff1fb0ae97c20eee4c1..bd8150f11b83dd42bf24f7a0fa4b4e2c409b5d47 100644
--- a/sdk/lib/_internal/pub/test/snapshot/upgrades_snapshot_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/snapshot/upgrades_snapshot_test.dart
@@ -14,34 +14,36 @@ main() {
   initConfig();
   integration("upgrades a snapshot when its package is upgraded", () {
     servePackages((builder) {
-      builder.serve("foo", "1.2.3", contents: [
-        d.dir("bin", [
-          d.file("hello.dart", "void main() => print('hello!');")
-        ])
-      ]);
+      builder.serve(
+          "foo",
+          "1.2.3",
+          contents: [
+              d.dir("bin", [d.file("hello.dart", "void main() => print('hello!');")])]);
     });
 
-    d.appDir({"foo": "any"}).create();
+    d.appDir({
+      "foo": "any"
+    }).create();
 
     pubGet(output: contains("Precompiled foo:hello."));
 
-    d.dir(p.join(appPath, '.pub', 'bin', 'foo'), [
-      d.matcherFile('hello.dart.snapshot', contains('hello!'))
-    ]).validate();
+    d.dir(
+        p.join(appPath, '.pub', 'bin', 'foo'),
+        [d.matcherFile('hello.dart.snapshot', contains('hello!'))]).validate();
 
     servePackages((builder) {
-      builder.serve("foo", "1.2.4", contents: [
-        d.dir("bin", [
-          d.file("hello.dart", "void main() => print('hello 2!');")
-        ])
-      ]);
+      builder.serve(
+          "foo",
+          "1.2.4",
+          contents: [
+              d.dir("bin", [d.file("hello.dart", "void main() => print('hello 2!');")])]);
     });
 
     pubUpgrade(output: contains("Precompiled foo:hello."));
 
-    d.dir(p.join(appPath, '.pub', 'bin', 'foo'), [
-      d.matcherFile('hello.dart.snapshot', contains('hello 2!'))
-    ]).validate();
+    d.dir(
+        p.join(appPath, '.pub', 'bin', 'foo'),
+        [d.matcherFile('hello.dart.snapshot', contains('hello 2!'))]).validate();
 
     var process = pubRun(args: ['foo:hello']);
     process.stdout.expect("hello 2!");