Rollup merge of #141431 - compiler-errors:open-drop, r=oli-obk

Emit dummy open drop for unsafe binder

Fixes rust-lang/rust#141394

We can't taint the body in wfcheck when we have a `T: Copy` bound failure, so we end up binding MIR here. Emit a dummy open drop so that drop elaboration doesn't fail.

r? oli-obk

Author: jieyouxu