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

sdk/lib/_internal/pub_generated/lib/src/cached_package.dart

Index: sdk/lib/_internal/pub_generated/lib/src/cached_package.dart
diff --git a/sdk/lib/_internal/pub/lib/src/cached_package.dart b/sdk/lib/_internal/pub_generated/lib/src/cached_package.dart
similarity index 94%
copy from sdk/lib/_internal/pub/lib/src/cached_package.dart
copy to sdk/lib/_internal/pub_generated/lib/src/cached_package.dart
index 94a500ed84bdb244718ef56bd68cef7c2f96c984..1e1c595e8d6ca1a01b40130a5f5994e71a670a21 100644
--- a/sdk/lib/_internal/pub/lib/src/cached_package.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/cached_package.dart
@@ -47,14 +47,16 @@ class CachedPackage extends Package {
 
   /// This will include the cached, transformed versions of files if [beneath]
   /// is within a cached directory, but not otherwise.
-  List<String> listFiles({String beneath, recursive: true,
-      bool useGitIgnore: false}) {
+  List<String> listFiles({String beneath, recursive: true, bool useGitIgnore:
+      false}) {
     if (beneath == null) {
       return super.listFiles(recursive: recursive, useGitIgnore: useGitIgnore);
     }
 
     if (_pathInCache(beneath)) return listDir(p.join(_cacheDir, beneath));
-    return super.listFiles(beneath: beneath, recursive: recursive,
+    return super.listFiles(
+        beneath: beneath,
+        recursive: recursive,
         useGitIgnore: useGitIgnore);
   }