[M-7]
Write a function that moves every element of an array down
one position in raster order.
Element x[i][j]
moves to x[i][j-1],
unless j is 0.
Then it is moved to x[i-1][NUMCOLS-1].
The first element of the array is moved to the last location in the array.
Before: After: 0 1 2 3 4 1 2 3 4 5 5 6 7 8 9 6 7 8 9 0
The previous testing framework can easily be modified for this puzzle.