cbc-n1qlback should log how many statements it has read from the input file

As part of debugging CCBC-907, I realised that n1qlback does not log anything once it has finished reading in the input file.

It would be useful for future debugging purposes if n1qlback logged the number of statements that it read in from the input file before beginning the execution loop, this has the added benefit of allowing the user to check if all statements in the file have been read in correctly.