Adjust compiler for HashMap::get_many_mut stabilization

Author: Urgau

Diff for: compiler/rustc_session/src/config/cfg.rs

@@ -421,7 +421,7 @@ impl CheckCfg {
                     Some(values_target_os),
                     Some(values_target_pointer_width),
                     Some(values_target_vendor),
-                ] = self.expecteds.get_many_mut(VALUES)
+                ] = self.expecteds.get_disjoint_mut(VALUES)
                 else {
                     panic!("unable to get all the check-cfg values buckets");
                 };

Diff for: compiler/rustc_session/src/lib.rs

@@ -2,7 +2,6 @@
 #![allow(internal_features)]
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
-#![feature(map_many_mut)]
 #![feature(rustc_attrs)]
 #![warn(unreachable_pub)]
 // tidy-alphabetical-end