define_method(name, Method) does not respect module_function

[eregon]

From rack/rack#2099 (comment)

It's because of

truffleruby/src/main/java/org/truffleruby/core/module/ModuleNodes.java

Line 1313 in a4a32f1

module.fields.addMethod(getContext(), this, internalMethod.withName(name));

vs
https://github.com/oracle/truffleruby/blob/a4a32f1556ca3ced88d2ab5a366a2c03bcc91d34/src/main/java/org/truffleruby/core/module/ModuleNodes.java#L1337C25-L1337C25

[eregon]

Fixed in 4dab7ea