Replace type_alias_impl_trait by min_type_alias_impl_trait with no actual changes in behaviour

This makes `type_alias_impl_trait` not actually do anything anymore

Author: oli-obk

alloc/src/lib.rs

@@ -142,7 +142,8 @@
 #![feature(alloc_layout_extra)]
 #![feature(trusted_random_access)]
 #![feature(try_trait)]
-#![feature(type_alias_impl_trait)]
+#![cfg_attr(bootstrap, feature(type_alias_impl_trait))]
+#![cfg_attr(not(bootstrap), feature(min_type_alias_impl_trait))]
 #![feature(associated_type_bounds)]
 #![feature(slice_group_by)]
 #![feature(decl_macro)]