promote the speed of convert files to RDDS

about convert files to RDDS there are 3 loops with files sequence in spark source.
loops files sequence:
1、files.map(...)
2、files.zip(fileRDDs)
3、files-size.foreach
It's will very time consuming when lots of files.So I do the following correction:
3 loops with files sequence => only one loop

Does your modification use ArrayBuffer, seems it is not used.