The doPartition method works incorrectly based on wrong assumption that register ranges doesn't have gaps

[PeterBorisenko]

To Reproduce Steps to reproduce the behavior:

1. Use the following data offsets with RegisterRange.HOLDING_REGISTER

   private int initDataOffsets[]= {
           0x0710, // device name
           0x0711, // device name
           0x0712, // device name
           0x0780, // loads count
           0x1200, // phases num
   };

2. Create batch read request

   BatchRead<Integer> batch = new BatchRead<Integer>();
   for (int i= 0; i < initDataOffsets.length; i++) {
   batch.addLocator(i, new ModbusLocator(16, RegisterRange.HOLDING_REGISTER, initDataOffsets[i],
   DataType.TWO_BYTE_INT_UNSIGNED, (byte) 0));
   }

3. Try to poll device:

   BatchResults<Integer> res= batchRead(master, batch);

4. If device doesn't have registers between 0x0712 and 0x0780 defined, there will be an error and res will be null.

Expected behavior List<ReadFunctionGroup<K>> functionGroups must be 3 here. But has 2.