don't test merge stability of point values: our BKD tree impl is not stable on 1D merge

lucene/test-framework/src/java/org/apache/lucene/index/BasePointFormatTestCase.java

@@ -919,4 +919,10 @@ public abstract class BasePointFormatTestCase extends BaseIndexFileFormatTestCas
     //dir = FSDirectory.open(createTempDir());
     return dir;
   }
+  
+  @Override
+  public void testMergeStability() {
+    // suppress this test from base class: merges for BKD trees are not stable because the tree created by merge will have a different
+    // structure than the tree created by adding points separately
+  }
 }