LUCENE-9555: Advance conjunction Iterator for two phase iteration (ap…

…ache#1943)

PR apache#1351 introduced a sort optimization where
documents can be skipped.
But there was a bug in case we were using two phase
approximation, as we would advance it without advancing
an overall conjunction iterator.

This patch fixed it.

Relates to apache#1351

lucene/core/src/java/org/apache/lucene/search/Weight.java

@@ -234,12 +234,11 @@ static int scoreRange(LeafCollector collector, DocIdSetIterator iterator, TwoPha
         }
         return currentDoc;
       } else {
-        final DocIdSetIterator approximation = twoPhase.approximation();
         while (currentDoc < end) {
           if ((acceptDocs == null || acceptDocs.get(currentDoc)) && twoPhase.matches()) {
             collector.collect(currentDoc);
           }
-          currentDoc = approximation.nextDoc();
+          currentDoc = iterator.nextDoc();
         }
         return currentDoc;
       }
@@ -258,8 +257,7 @@ static void scoreAll(LeafCollector collector, DocIdSetIterator iterator, TwoPhas
         }
       } else {
         // The scorer has an approximation, so run the approximation first, then check acceptDocs, then confirm
-        final DocIdSetIterator approximation = twoPhase.approximation();
-        for (int doc = approximation.nextDoc(); doc != DocIdSetIterator.NO_MORE_DOCS; doc = approximation.nextDoc()) {
+        for (int doc = iterator.nextDoc(); doc != DocIdSetIterator.NO_MORE_DOCS; doc = iterator.nextDoc()) {
           if ((acceptDocs == null || acceptDocs.get(doc)) && twoPhase.matches()) {
             collector.collect(doc);
           }