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

sdk/lib/_internal/pub_generated/test/global/run/runs_git_script_test.dart

+import '../../descriptor.dart' as d;
+import '../../test_pub.dart';
+main() {
+  initConfig();
+  integration('runs a script in a git package', () {
+    ensureGit();
+    d.git(
+        'foo.git',
+        [
+            d.libPubspec("foo", "1.0.0"),
+            d.dir("bin", [d.file("foo.dart", "main() => print('ok');")])]).create();
+    schedulePub(args: ["global", "activate", "-sgit", "../foo.git"]);
+    var pub = pubRun(global: true, args: ["foo"]);
+    pub.stdout.expect("ok");
+    pub.shouldExit();
+  });
+}