Allow specifying the limit of Coord in the opposite order to the Scale

[yutannihilation]

Fix #3952

ylim and xlim of coord_cartesian() can be specified in arbitrary order. But, ScaleContinuous$get_breaks() always expects the limits are in the same order to their order. If not, it returns NA and we'll see no ticks. So, the limits should be sorted before passing to it.

I think scale should raise more explicit warnings or errors, but it's out of scope of this PR.

devtools::load_all("~/repo/ggplot2/")
#> Loading ggplot2

library(patchwork)

d <- base::data.frame(
  x = 1:4,
  y = 1:4
)

p <- ggplot(d, aes(x, y)) +
  geom_point()

p1 <- p + coord_cartesian(ylim = c(1, 10)) + ggtitle("(usual plot)")
p2 <- p + coord_cartesian(ylim = c(10, 1)) + ggtitle("Coord is reversed")
p3 <- p + scale_y_reverse() + coord_cartesian(ylim = c(1, 10)) + ggtitle("Scale is reversed, but Coord is not")
p4 <- p + scale_y_reverse() + coord_cartesian(ylim = c(10, 1)) + ggtitle("Scale and Coord are reversed")

wrap_plots(p1, p2, p3, p4)

^{Created on 2020-04-22 by the reprex package (v0.3.0)}

[thomasp85]

LGTM