Tell the user if the binstub directory is not on their path.

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

Index: sdk/lib/_internal/pub_generated/test/global/binstubs/warns_if_not_on_path.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/warns_if_not_on_path.dart
similarity index 50%
copy from sdk/lib/_internal/pub_generated/test/global/binstubs/binstub_runs_precompiled_snapshot_test.dart
copy to sdk/lib/_internal/pub_generated/test/global/binstubs/warns_if_not_on_path.dart
index 0e6ee04ca96723ddf3645f00c5e41c4b9dec89be..3b73d25dd5fd612f6da5bdb0ec795307e45824b7 100644
--- a/sdk/lib/_internal/pub_generated/test/global/binstubs/binstub_runs_precompiled_snapshot_test.dart
+++ b/sdk/lib/_internal/pub_generated/test/global/binstubs/warns_if_not_on_path.dart
@@ -3,22 +3,18 @@ import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 main() {
   initConfig();
-  integration("the binstubs runs a precompiled snapshot if present", () {
+  integration("warns if the binstub directory is not on the path", () {
     servePackages((builder) {
       builder.serve("foo", "1.0.0", pubspec: {
         "executables": {
-          "foo-script": "script"
+          "script": null
         }
       },
           contents: [
-              d.dir("bin", [d.file("script.dart", "main(args) => print('ok');")])]);
+              d.dir("bin", [d.file("script.dart", "main(args) => print('ok \$args');")])]);
     });
-    schedulePub(args: ["global", "activate", "foo"]);
-    d.dir(
-        cachePath,
-        [
-            d.dir(
-                "bin",
-                [d.matcherFile("foo-script", contains("script.dart.snapshot"))])]).validate();
+    schedulePub(
+        args: ["global", "activate", "foo"],
+        output: contains("is not on your path"));
   });
 }