Rollup merge of #125711 - oli-obk:const_block_ice2, r=Nadrieril

Make `body_owned_by` return the `Body` instead of just the `BodyId`

fixes #125677

Almost all `body_owned_by` callers immediately called `body`, too, so just return `Body` directly.

This makes the inline-const query feeding more robust, as all calls to `body_owned_by` will now yield a body for inline consts, too.

I have not yet figured out a good way to make `tcx.hir().body()` return an inline-const body, but that can be done as a follow-up