minesweeper: remove number from input, add mines
minesweeper: remove number from input, add mines

an input containing only "8" implies that the student solution is
supposed to read a board with numbers and fill in the mines, which is
contrary to all other tests (read a board with mines, fill in the
numbers)

exercism/x-common,rpottsoh/x-common,ErikSchierboom/x-common,kgengler/x-common,petertseng/x-common,petertseng/x-common,jmluy/x-common,kgengler/x-common,exercism/x-common,jmluy/x-common,jmluy/x-common,ErikSchierboom/x-common,Vankog/problem-specifications,rpottsoh/x-common,Vankog/problem-specifications