fix(cdk-experimental/listbox): fix tests

Author: mmalerba

src/cdk-experimental/listbox/BUILD.bazel

@@ -28,6 +28,7 @@ ng_test_library(
         "//src/cdk-experimental/combobox",
         "//src/cdk/keycodes",
         "//src/cdk/testing/private",
+        "@npm//@angular/common",
         "@npm//@angular/forms",
         "@npm//@angular/platform-browser",
     ],