[perl #96212] Swapping of $< and $> should be deprecated

Pushed to doy/deprecate_uid_gid_swap. Didn't merge yet because the test
isn't really very accurate, it just checks for any of $<, $>, $(, or $)
being used on both the right and left side of a list assignment, but
would anyone be doing that outside of this context? Detecting an actual
swap would be pretty complicated.

-doy

---
via perlbug:  queue: perl5 status: open
https://rt.perl.org:443/rt3/Ticket/Display.html?id=96212

• Re: [perl #96212] Swapping of $< and $> should be deprecated by Leon Timmermans
• Re: [perl #96212] Swapping of $< and $> should be deprecated by Jesse Luehrs
• [perl #96212] Swapping of $< and $> should be deprecated by Jesse Luehrs via RT