slices: add sorting and comparison functions
Now that the `cmp` package exists, sorting and comparison functions from
`x/exp/slices` can be ported to the standard library, using the
`cmp.Ordered` type and the `cmp.Less` and `cmp.Compare` functions.
This move also includes adjustments to the discussions in #60091 w.r.t.
NaN handling and cmp vs. less functions, and adds Min/Max functions.
The final API is taken from
https://github.com/golang/go/issues/60091#issuecomment-
1553850782
Updates #60091
Change-Id: Id7e6c88035b60d4ddd0c48dd82add8e8bc4e22d3
Reviewed-on: https://go-review.googlesource.com/c/go/+/496078
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Eli Bendersky <eliben@google.com>
Run-TryBot: Eli Bendersky <eliben@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>