CC5 fix MixedIndexImplementationTest.shouldNotBeSelectedForCustomExpressions, changing default value of StorageAttachedIndexOptions.prioritize_over_legacy_index to 'true'.

The prioritize_over_legacy_index was introduced in 5.0.4 by CASSANDRA-20334 using a default of 'false'

Author: djatnieks

src/java/org/apache/cassandra/config/StorageAttachedIndexOptions.java

@@ -34,7 +34,7 @@ public class StorageAttachedIndexOptions
     public double zerocopy_used_threshold = DEFAULT_ZEROCOPY_USED_THRESHOLD;
     public double ann_brute_force_factor = DEFAULT_ANN_BRUTE_FORCE_FACTOR;
 
-    public volatile boolean prioritize_over_legacy_index = false;
+    public volatile boolean prioritize_over_legacy_index = true;
 
     public void validate()
     {

test/unit/org/apache/cassandra/index/sai/metrics/IndexSelectionTest.java

@@ -18,6 +18,8 @@
 
 package org.apache.cassandra.index.sai.metrics;
 
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 import org.junit.Test;
 
 import org.apache.cassandra.config.DatabaseDescriptor;
@@ -26,6 +28,18 @@
 
 public class IndexSelectionTest extends AbstractMetricsTest
 {
+    @BeforeClass
+    public static void setPrioritizeSAIOverLegacyIndex()
+    {
+        DatabaseDescriptor.setPrioritizeSAIOverLegacyIndex(false);
+    }
+
+    @AfterClass
+    public static void unsetPrioritizeSAIOverLegacyIndex()
+    {
+        DatabaseDescriptor.setPrioritizeSAIOverLegacyIndex(true);
+    }
+
     @Test
     public void shouldSelectLegacyIndexByDefault()
     {