Some final touches to ensure `./x.py test --stage 0 src/lib*` works

src/libcore/lib.rs

@@ -50,6 +50,7 @@
 
 // Since libcore defines many fundamental lang items, all tests live in a
 // separate crate, libcoretest, to avoid bizarre issues.
+#![cfg(not(test))]
 
 #![stable(feature = "core", since = "1.6.0")]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",

src/libcore/tests/lib.rs

@@ -46,6 +46,7 @@
 #![feature(reverse_bits)]
 #![feature(inclusive_range_methods)]
 #![feature(iterator_find_map)]
+#![feature(slice_internals)]
 
 extern crate core;
 extern crate test;

src/libcore/tests/num/uint_macros.rs

@@ -98,6 +98,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg(not(stage0))]
     fn test_reverse_bits() {
         assert_eq!(A.reverse_bits().reverse_bits(), A);
         assert_eq!(B.reverse_bits().reverse_bits(), B);

src/libstd/lib.rs

@@ -330,10 +330,10 @@
 // with a rustc without jemalloc.
 // FIXME(#44236) shouldn't need MSVC logic
 #![cfg_attr(all(not(target_env = "msvc"),
-                any(stage0, feature = "force_alloc_system")),
+                any(all(stage0, not(test)), feature = "force_alloc_system")),
             feature(global_allocator))]
 #[cfg(all(not(target_env = "msvc"),
-          any(stage0, feature = "force_alloc_system")))]
+          any(all(stage0, not(test)), feature = "force_alloc_system")))]
 #[global_allocator]
 static ALLOC: alloc_system::System = alloc_system::System;