Use a faster allocation size check in slice::from_raw_parts

library/core/src/lib.rs

@@ -191,6 +191,7 @@
 #![feature(extern_types)]
 #![feature(fundamental)]
 #![feature(if_let_guard)]
+#![feature(inline_const)]
 #![feature(intra_doc_pointers)]
 #![feature(intrinsics)]
 #![feature(lang_items)]