'it' marks itself as an anonreq for parameters method

Author: enebo

src/main/java/org/jruby/prism/builder/IRBuilderPrism.java

@@ -565,6 +565,7 @@ public void receiveBlockArgs(Node node) {
             Variable keywords = addResultInstr(new ReceiveKeywordsInstr(temp(), true, true));
             Variable v = getLocalVariable(symbol("it"), 0);
             markIt(staticScope);
+            ((IRClosure) scope).setArgumentDescriptors(new ArgumentDescriptor[] { new ArgumentDescriptor(ArgumentType.anonreq) });
             addInstr(new ReceivePreReqdArgInstr(v, keywords, 0));
         } else if (node instanceof BlockParametersNode params) {
             // FIXME: Missing locals?  Not sure how we handle those but I would have thought with a scope?