`./x.py test compiler/rustc_abi` no longer works

[Veykril]

This regressed with #128722
Running ./x.py test compiler/rustc_abi (as well as for most other compiler crates) no longer works, resulting in an error similar to the following:

error: none of the selected packages contains these features: jemalloc, llvm, max_level_info, rustc_use_parallel_compiler

[Veykril]

@rustbot claim

[Veykril]

Fixing this will be troublesome https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/.60parallel_compiler.60.20or.20.60rustc_use_parallel_compiler.60

[Veykril]

Whoops, I did not mean to close this with that PR (and I can't reopen it for some reason) this is still an issue