Function js::jsapi::JS_SetVersionForCompartment

pub unsafe extern "C" fn JS_SetVersionForCompartment(
    compartment: *mut JSCompartment, 
    version: JSVersion
)

Mutate the version on the compartment. This is generally discouraged, but necessary to support the version mutation in the js and xpc shell command set.

It would be nice to put this in jsfriendapi, but the linkage requirements of the shells make that impossible.