This follows after #26078, and #26313, adding `debug_info` to
more calls to `lu.wrap_init`.
As part of this I have changed the primitives `custom_vjp_call_jaxpr`
and `custom_lin` to take the `bwd` parameter as a `lu.WrappedFun`,
which carries debug info. Previously, this was a `Callable`, but in
almost all cases if was really ` lu.WrappedFun.call_wrapped`.