The `contourf`

function behaves very strangely when plotting data points on a logarithmic grid. Supplying the x- and y-positions of the data points and setting `scale=:log10`

completely messes up the plot. Here is a minimal example:

```
using Plots
xs = [10^i for i in range(-5, 5, length=50)]
data = [log(i*j) for i in xs, j in xs]
p1 = contourf(data, title="actual data")
p2 = contourf(xs, xs, data, scale=:log10, title="messed up data")
plot(p1, p2)
```

Am I am not sure if I am doing something wrong or if there is an issue with `contourf`

. Thanks for help!