Rollup merge of #68357 - ollie27:rustdoc_test_errors, r=GuillaumeGomez
rustdoc: Fix handling of compile errors when running `rustdoc --test`
* Call `abort_if_errors` so all errors actually stop rustdoc.
* Don't panic with "compiler aborted in rustdoc!", instead just exit to avoid the ugly panic message.
* Use rlib as the crate type when searching for doctests matching what is used for doc generation so `#[no_std]` crates don't create "no global memory allocator" errors.