Function get_property_on_prototype 

pub(crate) fn get_property_on_prototype(
    cx: &mut JSContext,
    proxy: HandleObject<'_>,
    receiver: HandleValue<'_>,
    id: HandleId<'_>,
    found: &mut bool,
    vp: MutableHandleValue<'_>,
) -> bool

Gets the property id on proxy’s prototype. If it exists, *found is set to true and *vp to the value, otherwise *found is set to false.

Returns false on JSAPI failure.