[DO NOT MERGE] Permit bootstrap changes for CI rustc if-unchanged

Author: jieyouxu

src/bootstrap/src/core/config/config.rs

@@ -66,6 +66,7 @@ use crate::{Command, GitInfo, OnceLock, TargetSelection, check_ci_llvm, helpers,
 #[rustfmt::skip] // We don't want rustfmt to oneline this list
 pub const RUSTC_IF_UNCHANGED_ALLOWED_PATHS: &[&str] = &[
     ":!library",
+    ":!src/bootstrap", // DO NOT MERGE, permit experimental bootstrap changes
     ":!src/tools",
     ":!src/librustdoc",
     ":!src/rustdoc-json-types",