Store the async-await compiled pub code directly in the repo.

sdk/lib/_internal/pub_generated/test/build/preserves_htaccess_test.dart

+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+main() {
+  initConfig();
+  integration("preserves .htaccess as a special case", () {
+    d.dir(
+        appPath,
+        [
+            d.appPubspec(),
+            d.dir(
+                'web',
+                [d.file('.htaccess', 'fblthp'), d.file('.hidden', 'asdfgh')])]).create();
+    schedulePub(
+        args: ["build"],
+        output: new RegExp(r'Built \d+ files? to "build".'));
+    d.dir(
+        appPath,
+        [
+            d.dir(
+                'build',
+                [
+                    d.dir(
+                        'web',
+                        [d.file('.htaccess', 'fblthp'), d.nothing('.hidden')])])]).validate();
+  });
+}