docs: public static ScriptableObject getGlobal(Context cx) {
          final String GLOBAL_CLASS = "org.mozilla.javascript.tools.shell.Global";
          Class<?> globalClass = Kit.classOrNull(GLOBAL_CLASS);
          if (globalClass != null) {
              try {
                  Class<?>[] parm = { ScriptRuntime.ContextClass };
                  Constructor<?> globalClassCtor = globalClass.getConstructor(parm);
                  Object[] arg = { cx };
                  return (ScriptableObject) globalClassCtor.newInstance(arg);
              }
              catch (RuntimeException e) {
                  throw e;
              }
              catch (Exception e) {
                  // fall through...
              }
          }
          return new ImporterTopLevel(cx);
      }