fixup! Inject compiler_builtins during postprocessing rather than via AST

Author: tgross35

compiler/rustc_metadata/src/creader.rs

@@ -1055,7 +1055,7 @@ impl<'a, 'tcx> CrateLoader<'a, 'tcx> {
         // relevant symbols aren't otherwise provided.
         let Ok(cnum) = self.maybe_resolve_crate(
             sym::compiler_builtins,
-            CrateDepKind::Implicit,
+            CrateDepKind::Explicit,
             CrateOrigin::Injected,
         ) else {
             info!("`compiler_builtins` not resolved");