Fix NFAQuery in TestRegexpRandom2 (#12793)

Author: zhaih

lucene/core/src/test/org/apache/lucene/search/TestRegexpRandom2.java

@@ -181,7 +181,9 @@ protected void assertSame(String regexp) throws IOException {
             0,
             RegexpQuery.DEFAULT_PROVIDER,
             0,
-            MultiTermQuery.CONSTANT_SCORE_BLENDED_REWRITE,
+            // TODO: The NFA query is not able to use rewrite method that will utilize the
+            // concurrency
+            MultiTermQuery.CONSTANT_SCORE_BOOLEAN_REWRITE,
             false);
     DumbRegexpQuery dumb = new DumbRegexpQuery(new Term(fieldName, regexp), RegExp.NONE);