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

sdk/lib/_internal/pub_generated/test/preprocess_test.dart

Index: sdk/lib/_internal/pub_generated/test/preprocess_test.dart
diff --git a/sdk/lib/_internal/pub/test/preprocess_test.dart b/sdk/lib/_internal/pub_generated/test/preprocess_test.dart
similarity index 90%
copy from sdk/lib/_internal/pub/test/preprocess_test.dart
copy to sdk/lib/_internal/pub_generated/test/preprocess_test.dart
index 4f43dd8129e0ce771ad9bc522d22c1bb907d7c3e..0cd4eadd0d041d4aab5b5890f03590e927fabc86 100644
--- a/sdk/lib/_internal/pub/test/preprocess_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/preprocess_test.dart
@@ -248,22 +248,24 @@ after
       });
 
       test("disallows if with no package", () {
-        expect(() => _preprocess('//# if <=1.0.0\n//# end'),
+        expect(
+            () => _preprocess('//# if <=1.0.0\n//# end'),
             throwsFormatException);
       });
 
       test("disallows invalid version constraint", () {
-        expect(() => _preprocess('//# if barback >=1.0\n//# end'),
+        expect(
+            () => _preprocess('//# if barback >=1.0\n//# end'),
             throwsFormatException);
       });
 
       test("disallows dangling end", () {
-        expect(() => _preprocess('//# end'),
-            throwsFormatException);
+        expect(() => _preprocess('//# end'), throwsFormatException);
       });
 
       test("disallows if without end", () {
-        expect(() => _preprocess('//# if barback >=1.0.0'),
+        expect(
+            () => _preprocess('//# if barback >=1.0.0'),
             throwsFormatException);
       });
 
@@ -273,8 +275,7 @@ after
 //# if barback >= 1.5.0
 //# end
 //# end
-'''),
-            throwsFormatException);
+'''), throwsFormatException);
       });
     });
 
@@ -284,7 +285,8 @@ after
       });
 
       test("disallows else without end", () {
-        expect(() => _preprocess('//# if barback >=1.0.0\n//# else'),
+        expect(
+            () => _preprocess('//# if barback >=1.0.0\n//# else'),
             throwsFormatException);
       });
 
@@ -299,5 +301,6 @@ after
   });
 }
 
-String _preprocess(String input) =>
-    preprocess(input, {'barback': new Version.parse("1.2.3")}, 'source/url');
+String _preprocess(String input) => preprocess(input, {
+  'barback': new Version.parse("1.2.3")
+}, 'source/url');