Create binstubs for executables when activating a package.

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

Index: sdk/lib/_internal/pub_generated/test/global/binstubs/unknown_explicit_executable_test.dart
diff --git a/sdk/lib/_internal/pub_generated/test/global/binstubs/unknown_explicit_executable_test.dart b/sdk/lib/_internal/pub_generated/test/global/binstubs/unknown_explicit_executable_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..8df940af2eaa4aa193ff094bdeebc2e10cdfca1f
--- /dev/null
+++ b/sdk/lib/_internal/pub_generated/test/global/binstubs/unknown_explicit_executable_test.dart
@@ -0,0 +1,32 @@
+import 'package:scheduled_test/scheduled_stream.dart';
+import '../../../lib/src/exit_codes.dart' as exit_codes;
+import '../../descriptor.dart' as d;
+import '../../test_pub.dart';
+main() {
+  initConfig();
+  integration("errors on an unknown explicit executable", () {
+    d.dir("foo", [d.pubspec({
+        "name": "foo",
+        "executables": {
+          "one": "one"
+        }
+      }),
+          d.dir("bin", [d.file("one.dart", "main() => print('ok');")])]).create();
+    var pub = startPub(
+        args: [
+            "global",
+            "activate",
+            "--source",
+            "path",
+            "../foo",
+            "-x",
+            "who",
+            "-x",
+            "one",
+            "--executable",
+            "wat"]);
+    pub.stdout.expect(consumeThrough("Installed executable one."));
+    pub.stderr.expect("Unknown executables wat and who.");
+    pub.shouldExit(exit_codes.DATA);
+  });
+}