Model File.listFiles using undefined instead of allocation

Summary: Express model of java.io.File.listFiles using InferUndefined.object_undefined
instead of new File[...].

public

Reviewed By: jeremydubreil, sblackshear

Differential Revision: D2649406

fb-gh-sync-id: 93c5bb5

infer/models/java/src/java/io/File.java

@@ -18,7 +18,7 @@ public class File {
         if (InferUndefined.boolean_undefined()) {
             return null;
         } else {
-            return new File[InferUndefined.int_undefined()];
+            return (File[])InferUndefined.object_undefined();
         }
     }