Fix dealing with non-method descriptors in LookupSpecialMethod

Author: msimacek

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/call/special/LookupSpecialBaseNode.java

@@ -81,7 +81,8 @@ public final Object execute(VirtualFrame frame, Object type, Object receiver) {
                 throw pe;
             }
         }
-        return descriptor;
+        // CPython considers non-descriptors already bound
+        return new BoundDescriptor(descriptor);
     }
 
     private LookupInheritedAttributeNode ensureLookupGet() {

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/call/special/LookupSpecialMethodNode.java

@@ -109,7 +109,8 @@ Object lookup(Object type, Object name, Object receiver, boolean ignoreDescripto
                     throw pe;
                 }
             }
-            return descriptor;
+            // CPython considers non-descriptors already bound
+            return new BoundDescriptor(descriptor);
         }
     }
 }