Make binstubs run snapshots directly when possible.

sdk/lib/_internal/pub_generated/test/global/binstubs/binstub_runs_precompiled_snapshot_test.dart

Index: sdk/lib/_internal/pub_generated/test/global/binstubs/binstub_runs_precompiled_snapshot_test.dart
diff --git a/sdk/lib/_internal/pub_generated/test/global/binstubs/binstub_runs_precompiled_snapshot_test.dart b/sdk/lib/_internal/pub_generated/test/global/binstubs/binstub_runs_precompiled_snapshot_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..0e6ee04ca96723ddf3645f00c5e41c4b9dec89be
--- /dev/null
+++ b/sdk/lib/_internal/pub_generated/test/global/binstubs/binstub_runs_precompiled_snapshot_test.dart
@@ -0,0 +1,24 @@
+import 'package:scheduled_test/scheduled_test.dart';
+import '../../descriptor.dart' as d;
+import '../../test_pub.dart';
+main() {
+  initConfig();
+  integration("the binstubs runs a precompiled snapshot if present", () {
+    servePackages((builder) {
+      builder.serve("foo", "1.0.0", pubspec: {
+        "executables": {
+          "foo-script": "script"
+        }
+      },
+          contents: [
+              d.dir("bin", [d.file("script.dart", "main(args) => print('ok');")])]);
+    });
+    schedulePub(args: ["global", "activate", "foo"]);
+    d.dir(
+        cachePath,
+        [
+            d.dir(
+                "bin",
+                [d.matcherFile("foo-script", contains("script.dart.snapshot"))])]).validate();
+  });
+}