LUCENE-8142: Fix QueryUtils to only call getMaxScore when it is legal to do so.

lucene/test-framework/src/java/org/apache/lucene/search/AssertingScorer.java

@@ -99,7 +99,7 @@ public class AssertingScorer extends Scorer {
     assert iterating() : state;
     final float score = in.score();
     assert !Float.isNaN(score) : "NaN score for in="+in;
-    assert score <= getMaxScore(DocIdSetIterator.NO_MORE_DOCS);
+    assert lastShallowTarget == -1 || score <= getMaxScore(docID());
     assert Float.compare(score, 0f) >= 0 : score;
     return score;
   }