Handle foreign objects much like #method_missing

* Which means returning MISSING if RETURN_MISSING is used.
  RETURN_MISSING seems never used on foreign objects, except for
  defined?(recv.foo(*args)) where it would not work for a foreign object anyway.

Author: eregon

src/main/java/org/truffleruby/language/dispatch/DispatchNode.java

@@ -127,15 +127,15 @@ public Object execute(VirtualFrame frame, Object receiver, String methodName, Ru
         final InternalMethod method = methodLookup.execute(frame, metaclass, methodName, config);
 
         if (methodMissing.profile(method == null || method.isUndefined())) {
-            if (isForeignCall.profile(metaclass == getContext().getCoreLibrary().truffleInteropForeignClass)) {
-                return callForeign(receiver, methodName, block, arguments);
-            }
-
             switch (config.missingBehavior) {
                 case RETURN_MISSING:
                     return MISSING;
                 case CALL_METHOD_MISSING:
-                    return callMethodMissing(frame, receiver, methodName, block, arguments);
+                    if (isForeignCall.profile(metaclass == getContext().getCoreLibrary().truffleInteropForeignClass)) {
+                        return callForeign(receiver, methodName, block, arguments);
+                    } else {
+                        return callMethodMissing(frame, receiver, methodName, block, arguments);
+                    }
             }
         }