findbugs: remove index masking field

Author: cosminbasca

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/iterator/PIntegerSequenceIterator.java

@@ -31,7 +31,6 @@
 public final class PIntegerSequenceIterator extends PIntegerIterator {
 
     final IntSequenceStorage sequence;
-    int index;
 
     public PIntegerSequenceIterator(Object clazz, DynamicObject storage, IntSequenceStorage sequence) {
         super(clazz, storage);