Update Rust toolchain nightly-2024-05-24 (rust-lang#3212)

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Fix usage of `tcx.crates()`:
rust-lang#124976.

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 and MIT licenses.

Author: qinheping

kani-compiler/src/kani_middle/resolve.rs

@@ -247,7 +247,7 @@ where
 /// Resolves an external crate name.
 fn resolve_external(tcx: TyCtxt, name: &str) -> Option<DefId> {
     debug!(?name, "resolve_external");
-    tcx.crates(()).iter().find_map(|crate_num| {
+    tcx.used_crates(()).iter().find_map(|crate_num| {
         let crate_name = tcx.crate_name(*crate_num);
         if crate_name.as_str() == name {
             Some(DefId { index: CRATE_DEF_INDEX, krate: *crate_num })

rust-toolchain.toml

@@ -2,5 +2,5 @@
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
 [toolchain]
-channel = "nightly-2024-05-23"
+channel = "nightly-2024-05-24"
 components = ["llvm-tools-preview", "rustc-dev", "rust-src", "rustfmt"]