Add an isless method for Base.UUID

[ararslan]

This permits the removal of a pirated method in Pkg.

[ararslan]

The macOS failure is unrelated, but concerning:

ccache: error: Could not find compiler "gfortran" in PATH
Traceback (most recent call last):
  File "/Users/travis/build/JuliaLang/julia/contrib/normalize_triplet.py", line 118, in <module>
    }[sys.argv[2][0]]

I haven't seen that before.

Also it looks like FreeBSD isn't being triggered?

[KristofferC]

Pkg could just implement the sorting using a by argument if it wants to sort by UUID?

[StefanKarpinski]

I do get that the sort order for UUIDs is kind of arbitrary since the values don't mean anything but how else would you sort them? Sometimes you just want to sort some UUIDs in a predictable order and this is pretty much the only reasonable choice.

[StefanKarpinski]

macOS failure was #30949 (unrelated).