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

sdk/lib/_internal/pub_generated/test/hosted/version_negotiation_test.dart

Index: sdk/lib/_internal/pub_generated/test/hosted/version_negotiation_test.dart
diff --git a/sdk/lib/_internal/pub/test/hosted/version_negotiation_test.dart b/sdk/lib/_internal/pub_generated/test/hosted/version_negotiation_test.dart
similarity index 81%
copy from sdk/lib/_internal/pub/test/hosted/version_negotiation_test.dart
copy to sdk/lib/_internal/pub_generated/test/hosted/version_negotiation_test.dart
index f6026186ab45b7da243a69ed71315886f8942fe7..7d2914e917e0752a20dd5e2726ab9ebb459e01cb 100644
--- a/sdk/lib/_internal/pub/test/hosted/version_negotiation_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/hosted/version_negotiation_test.dart
@@ -30,7 +30,8 @@ main() {
       var pub = startPub(args: [command.name]);
 
       server.handle('GET', '/api/packages/foo', (request) {
-        expect(request.headers['accept'],
+        expect(
+            request.headers['accept'],
             equals('application/vnd.pub.v2+json'));
         return new shelf.Response(200);
       });
@@ -52,14 +53,17 @@ main() {
 
       var pub = startPub(args: [command.name]);
 
-      server.handle('GET', '/api/packages/foo',
+      server.handle(
+          'GET',
+          '/api/packages/foo',
           (request) => new shelf.Response(406));
 
       pub.shouldExit(1);
 
-      pub.stderr.expect(emitsLines(
-          "Pub 0.1.2+3 is incompatible with the current version of localhost.\n"
-          "Upgrade pub to the latest version and try again."));
+      pub.stderr.expect(
+          emitsLines(
+              "Pub 0.1.2+3 is incompatible with the current version of localhost.\n"
+                  "Upgrade pub to the latest version and try again."));
     });
   });
 }