remove use of java stream api and consequent allocations in mutateAtomically

avoid array copy when xoring MerkleTree hashes

Author: Matt Byrd

src/java/org/apache/cassandra/service/StorageProxy.java

@@ -1441,8 +1441,11 @@ public static void mutateAtomically(List<Mutation> mutations,
         boolean attributeNonAccordLatency = true;
         long nonAccordEndTime = -1;
 
-        if (mutations.stream().anyMatch(mutation -> Keyspace.open(mutation.getKeyspaceName()).getReplicationStrategy().hasTransientReplicas()))
-            throw new AssertionError("Logged batches are unsupported with transient replication");
+        for (IMutation mutation : mutations)
+        {
+            if (Keyspace.open(mutation.getKeyspaceName()).getReplicationStrategy().hasTransientReplicas())
+                throw new AssertionError("Logged batches are unsupported with transient replication");
+        }
 
         try
         {

src/java/org/apache/cassandra/utils/MerkleTree.java

@@ -1482,7 +1482,7 @@ static byte[] xor(byte[] left, byte[] right)
     {
         assert left.length == right.length;
 
-        byte[] out = Arrays.copyOf(right, right.length);
+        byte[] out = new byte[right.length];
         for (int i = 0; i < left.length; i++)
             out[i] = (byte)((left[i] & 0xFF) ^ (right[i] & 0xFF));
         return out;