generation of col_index of intel spmm benchmark has bugs

[allenaann]

m n k: 4 2 2 values: 0.333333 0.471405 0.57735 0.666667 0.745356 0.816497 0.881917 0.942809 col_index: 0 1 0 1 1 2 1 2 row_start: 0 2 4 6 8 x: -100.89 -99.89 -98.89 -97.89

the col_index is impossible to be 2