smoke_test_real_sysroot_cargo fails on rustc 1.86.0-beta.1

[lnicola]

test tests::smoke_test_real_sysroot_cargo ... FAILED

failures:

---- tests::smoke_test_real_sysroot_cargo stdout ----

thread 'tests::smoke_test_real_sysroot_cargo' panicked at crates/base-db/src/input.rs:531:74:
no entry found for key
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    tests::smoke_test_real_sysroot_cargo

[Veykril]

Probably #18806? That is not a good failure ...

That or the recent sysroot loading changes (we had a couple)

[Veykril]

Looks like something about the sysroot has changed

[Veykril]

So the cause here is that alloc depends on rand which now depends on zerocopy which depends on zerocopy-derive. We don't build proc-macros the sysroot though so that fails to load. This is the first time the sysroot depends on a 3rd party proc-macro which is why we only saw this issue now.