Rollup merge of #144125 - GuillaumeGomez:new-annotations, r=Kobzol

Add new `ignore-backends` and `needs-backends` tests annotations

Part of rust-lang/compiler-team#891.

Next step will be to add these annotations in the files where either the output is different based on the codegen (like `asm` tests) or that are known to fail in the GCC backend.

cc `@oli-obk` `@antoyo`
r? `@Kobzol`

Author: GuillaumeGomez