Don't use mir_keys for deciding whether to load MIR in deduced_param_attrs

This can cause query cycles in const eval, when const eval checks the ABI of functions, as mir_keys can depend on `typeck` to find all newly generated items (like const blocks)

Author: oli-obk

compiler/rustc_mir_transform/src/deduce_param_attrs.rs

@@ -182,7 +182,7 @@ pub fn deduced_param_attrs<'tcx>(
     }
 
     // Don't deduce any attributes for functions that have no MIR.
-    if !tcx.is_mir_available(def_id) {
+    if tcx.hir().maybe_body_owned_by(def_id).is_none() {
         return &[];
     }