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

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

Index: sdk/lib/_internal/pub_generated/test/ascii_tree_test.dart
diff --git a/sdk/lib/_internal/pub/test/ascii_tree_test.dart b/sdk/lib/_internal/pub_generated/test/ascii_tree_test.dart
similarity index 72%
copy from sdk/lib/_internal/pub/test/ascii_tree_test.dart
copy to sdk/lib/_internal/pub_generated/test/ascii_tree_test.dart
index 96d81ee7bc53fe8180dfd6ecf8ccb68d18809a3b..04cf1f7fa44843b49419c596a33c463c554a22b1 100644
--- a/sdk/lib/_internal/pub/test/ascii_tree_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/ascii_tree_test.dart
@@ -19,17 +19,16 @@ main() {
 
     test('up to ten files in one directory are shown', () {
       var files = [
-        "dir/a.dart",
-        "dir/b.dart",
-        "dir/c.dart",
-        "dir/d.dart",
-        "dir/e.dart",
-        "dir/f.dart",
-        "dir/g.dart",
-        "dir/h.dart",
-        "dir/i.dart",
-        "dir/j.dart"
-      ];
+          "dir/a.dart",
+          "dir/b.dart",
+          "dir/c.dart",
+          "dir/d.dart",
+          "dir/e.dart",
+          "dir/f.dart",
+          "dir/g.dart",
+          "dir/h.dart",
+          "dir/i.dart",
+          "dir/j.dart"];
       expect(tree.fromFiles(files), equals("""
 '-- dir
     |-- a.dart
@@ -47,18 +46,17 @@ main() {
 
     test('files are elided if there are more than ten', () {
       var files = [
-        "dir/a.dart",
-        "dir/b.dart",
-        "dir/c.dart",
-        "dir/d.dart",
-        "dir/e.dart",
-        "dir/f.dart",
-        "dir/g.dart",
-        "dir/h.dart",
-        "dir/i.dart",
-        "dir/j.dart",
-        "dir/k.dart"
-      ];
+          "dir/a.dart",
+          "dir/b.dart",
+          "dir/c.dart",
+          "dir/d.dart",
+          "dir/e.dart",
+          "dir/f.dart",
+          "dir/g.dart",
+          "dir/h.dart",
+          "dir/i.dart",
+          "dir/j.dart",
+          "dir/k.dart"];
       expect(tree.fromFiles(files), equals("""
 '-- dir
     |-- a.dart
@@ -73,18 +71,17 @@ main() {
 
     test('files are not elided at the top level', () {
       var files = [
-        "a.dart",
-        "b.dart",
-        "c.dart",
-        "d.dart",
-        "e.dart",
-        "f.dart",
-        "g.dart",
-        "h.dart",
-        "i.dart",
-        "j.dart",
-        "k.dart"
-      ];
+          "a.dart",
+          "b.dart",
+          "c.dart",
+          "d.dart",
+          "e.dart",
+          "f.dart",
+          "g.dart",
+          "h.dart",
+          "i.dart",
+          "j.dart",
+          "k.dart"];
       expect(tree.fromFiles(files), equals("""
 |-- a.dart
 |-- b.dart
@@ -102,28 +99,27 @@ main() {
 
     test('a complex example', () {
       var files = [
-        "TODO",
-        "example/console_example.dart",
-        "example/main.dart",
-        "example/web copy/web_example.dart",
-        "test/absolute_test.dart",
-        "test/basename_test.dart",
-        "test/dirname_test.dart",
-        "test/extension_test.dart",
-        "test/is_absolute_test.dart",
-        "test/is_relative_test.dart",
-        "test/join_test.dart",
-        "test/normalize_test.dart",
-        "test/relative_test.dart",
-        "test/split_test.dart",
-        ".gitignore",
-        "README.md",
-        "lib/path.dart",
-        "pubspec.yaml",
-        "test/all_test.dart",
-        "test/path_posix_test.dart",
-        "test/path_windows_test.dart"
-      ];
+          "TODO",
+          "example/console_example.dart",
+          "example/main.dart",
+          "example/web copy/web_example.dart",
+          "test/absolute_test.dart",
+          "test/basename_test.dart",
+          "test/dirname_test.dart",
+          "test/extension_test.dart",
+          "test/is_absolute_test.dart",
+          "test/is_relative_test.dart",
+          "test/join_test.dart",
+          "test/normalize_test.dart",
+          "test/relative_test.dart",
+          "test/split_test.dart",
+          ".gitignore",
+          "README.md",
+          "lib/path.dart",
+          "pubspec.yaml",
+          "test/all_test.dart",
+          "test/path_posix_test.dart",
+          "test/path_windows_test.dart"];
 
       expect(tree.fromFiles(files), equals("""
 |-- .gitignore