Expose Once within std-shims, bump spin to 0.9

This is technically a semver break due to bumping spin to 0.10, with the types
from spin being directly exposed. Long-term, we should not directly expose spin
but instead have our own types which are thin wrappers around spin (clearly
defining our API and allowing upgrading internals without breaking semver).

common/std-shims/src/sync.rs

@@ -26,6 +26,6 @@ mod mutex_shim {
 pub use mutex_shim::{ShimMutex as Mutex, MutexGuard};
 
 #[cfg(feature = "std")]
-pub use std::sync::LazyLock;
+pub use std::sync::{OnceLock, LazyLock};
 #[cfg(not(feature = "std"))]
-pub use spin::Lazy as LazyLock;
+pub use spin::{Once as OnceLock, Lazy as LazyLock};