Ajax data encoding ignored when passing data in as map

[[email protected]…]

When creating an ajax request with a different encoding than UTF-8 and using a map for the data option, the ajax encoding is being ignored while converting the map to a query string. This is probably due to the fact that the jquery.param method that is used to convert the map to a query string uses the javascript method encodeURIComponent which creates an UTF-8 encoded representation of the parameters.

[dmethvin]

Duplicate of #11097.