Auto merge of rust-lang#94290 - Mark-Simulacrum:bump-bootstrap, r=pietroalbini

Bump bootstrap to 1.60

This bumps the bootstrap compiler to 1.60 and cleans up cfgs and Span's rustc_pass_by_value (enabled by the bootstrap bump).

Author: bors

compiler/rustc_ast_lowering/src/lib.rs

@@ -35,7 +35,7 @@
 #![feature(let_else)]
 #![feature(never_type)]
 #![recursion_limit = "256"]
-#![cfg_attr(not(bootstrap), allow(rustc::potential_query_instability))]
+#![allow(rustc::potential_query_instability)]
 
 use rustc_ast::token::{self, Token};
 use rustc_ast::tokenstream::{CanSynthesizeMissingTokens, TokenStream, TokenTree};

compiler/rustc_ast_passes/src/lib.rs

@@ -8,7 +8,7 @@
 #![feature(box_patterns)]
 #![feature(let_else)]
 #![recursion_limit = "256"]
-#![cfg_attr(not(bootstrap), allow(rustc::potential_query_instability))]
+#![allow(rustc::potential_query_instability)]
 
 pub mod ast_validation;
 pub mod feature_gate;