DEPLOY BY 9/16: Swap out jQuery.JSON for native methods

The jQuery.JSON module is being removed in 1.25, which is going out to
all sorts of sites on 9/16.

Change-Id: I448264b651b7c5e291985476c23b54e09b2a6540
Merge "DEPLOY BY 9/16: Swap out jQuery.JSON for native methods"