8176895: (fc) Split java/nio/channels/FileChannel/Transfer.java into smaller tests Summary: Move sub-tests writing 4GB and 6GB files into two separate tests Reviewed-by: clanger

^build/
^dist/
^.idea/
nbproject/private/
^webrev
^.src-rev$
^.jib/
.DS_Store
.metadata/
.recommenders/