Auto merge of #144249 - GuillaumeGomez:asm-tests, r=jieyouxu

Rename `tests/{assembly,codegen}` into `tests/{assembly,codegen}-llvm` and ignore these testsuites if configured backend doesn't match

Follow-up of rust-lang/rust#144125.

This PR changes `compiletest` so that `asm` tests are only run if they match the current codegen backend. To better reflect it, I renamed the `tests/ui/asm` folder into `tests/ui/asm-llvm`. Like that, we can add new asm tests for other backends if we want without needing to add extra code to `compiletest`.

Next step will be to use the new code annotations added in rust-lang/rust#144125 to ignore ui tests failing in cg_gcc until it's fixed on our side.

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

Author: bors