ci: Pin nightly toolchain for sanitizers to nightly-2024-03-13

Author: taiki-e

.github/workflows/ci.yml

@@ -256,7 +256,8 @@ jobs:
     steps:
       - uses: taiki-e/checkout-action@v1
       - name: Install Rust
-        run: rustup toolchain install nightly --component rust-src && rustup default nightly
+        # TODO: LLVM bug https://github.com/rust-lang/rust/issues/122476
+        run: rustup toolchain install nightly-2024-03-13 --component rust-src && rustup default nightly-2024-03-13
       - run: cargo -Z build-std test --workspace --all-features --target x86_64-unknown-linux-gnu --lib --tests
         env:
           # TODO: Once `cfg(sanitize = "..")` is stable, replace