Prism now generates all this special flag code. Only ask for this generated code in main or inline code

Author: enebo

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

@@ -75,6 +75,7 @@
 import java.util.Map;
 import java.util.Set;
 
+import static org.jruby.api.Warn.warning;
 import static org.jruby.ir.instructions.RuntimeHelperCall.Methods.*;
 import static org.jruby.runtime.CallType.VARIABLE;
 import static org.jruby.runtime.ThreadContext.*;