[Caja] Re: Mitigate top-level vars and typeof differences between ES5 and ES5/3 with rewriting (issue 6827077)

[kpreid . switchb . org]

We should also get rid of the es53 warnings
  TOP_LEVEL_VAR_INCOMPATIBLE_WITH_CAJA
  TOP_LEVEL_FUNC_INCOMPATIBLE_WITH_CAJA
since they are about what we're fixing here, right?

https://codereview.appspot.com/6827077/