Auto merge of #84614 - RalfJung:daily, r=Mark-Simulacrum

don't enable parking_lot nightly features

Having the compiler itself depend on external libraries that use nightly features can lead to "fun" bootstrap situations. Within the rustc repo we use `cfg(bootstrap)` to resolve those, but that is not a reasonable option for external dependencies.

So I propose we stop enabling the "nightly" feature of `parking_lot` here. In my experiments, this then indeed leads to the feature not being enabled (i.e., nothing else enables it), and everything still builds. However, this means parking_lot's `RwLock` will no longer have hardware lock elision for readers -- I hope that is okay to lose in exchange for less bootstrap brain twisting. ;)

Cc `@Amanieu`

compiler/rustc_data_structures/Cargo.toml

@@ -32,7 +32,6 @@ tempfile = "3.2"
 
 [dependencies.parking_lot]
 version = "0.11"
-features = ["nightly"]
 
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["fileapi", "psapi"] }