In branch-1 L2 BC should not be the victimhandler of L1 BC when using combined BC

  LruBlockCache l1 = getL1(conf);
    // blockCacheDisabled is set as a side-effect of getL1Internal(), so check it again after the call.
    if (blockCacheDisabled) return null;
    BlockCache l2 = getL2(conf);
    if (l2 == null) {
      GLOBAL_BLOCK_CACHE_INSTANCE = l1;
    } else {
      boolean useExternal = conf.getBoolean(EXTERNAL_BLOCKCACHE_KEY, EXTERNAL_BLOCKCACHE_DEFAULT);
      boolean combinedWithLru = conf.getBoolean(BUCKET_CACHE_COMBINED_KEY,
        DEFAULT_BUCKET_CACHE_COMBINED);
      if (useExternal) {
        GLOBAL_BLOCK_CACHE_INSTANCE = new InclusiveCombinedBlockCache(l1, l2);
      } else {
        if (combinedWithLru) {
          GLOBAL_BLOCK_CACHE_INSTANCE = new CombinedBlockCache(l1, l2);
        } else {
          // L1 and L2 are not 'combined'.  They are connected via the LruBlockCache victimhandler
          // mechanism.  It is a little ugly but works according to the following: when the
          // background eviction thread runs, blocks evicted from L1 will go to L2 AND when we get
          // a block from the L1 cache, if not in L1, we will search L2.
          GLOBAL_BLOCK_CACHE_INSTANCE = l1;
        }
      }
      l1.setVictimCache(l2);
    }