create a mesh grid from major and minor values.
given two arrays major_values and minor_values, this function generates a pair of 2D arrays, representing the major-grid and minor-grid.
the major-grid contains rows of major_values, and the minor-grid contains columns of minor_values.

const
y_values = [1, 2, 3],
x_values = [4, 5]
[yy_grid, xx_grid] = meshGrid(y_values, x_values)
yy_grid === [
[1, 1],
[2, 2],
[3, 3],
]
xx_grid === [
[4, 5],
[4, 5],
[4, 5],
]