Implement lint to warn about relative `core`/`kernel` paths in macro
definitions.

Fixes #14472

Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>
Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>

Create `tests/ui/relative_path_in_macro_definition.rs` with positive and
negative cases to verify lint behavior.

Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>
Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>

Add `#![allow(clippy::relative_path_in_macro_definition)]` to
`incompatible_msrv.rs`, `swap_ptr_to_ref_unfixable.rs`, and
`arithmetic_side_effects.rs` to avoid lint interference. Update
corresponding `.stderr` files.

Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>
Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>