Fix #13809: Quote IdentifierNames reserved by any version of ECMA-262

cc @dmethvin @timmywil

Consensus was to rename the property, but Sizzle already quotes it and I'd rather not burn a semver major version bump over something so cosmetic and trivial. Thoughts?

```
   raw     gz Sizes                                                            
271993  80754 dist/jquery.js                                                   
 92981  32679 dist/jquery.min.js                                               

   raw     gz Compared to 1.x-master @ d605322c105f4edc37e9a6357af23c4cee53c2cc
    +9     +4 dist/jquery.js                                                   
    +9     +1 dist/jquery.min.js
```