[Perl/perl5] 6ac93b: Add builtin:: funcs for handling weakrefs

[Paul Evans via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: 6ac93b496cce8882a9d5494bfedb84f4da7e0aee
      
https://github.com/Perl/perl5/commit/6ac93b496cce8882a9d5494bfedb84f4da7e0aee
  Author: Paul "LeoNerd" Evans <leon...@leonerd.org.uk>
  Date:   2021-12-04 (Sat, 04 Dec 2021)

  Changed paths:
    M builtin.c
    M ext/Opcode/Opcode.pm
    M lib/B/Deparse.pm
    M lib/B/Deparse.t
    M lib/B/Op_private.pm
    M lib/builtin.pm
    M lib/builtin.t
    M opcode.h
    M opnames.h
    M pod/perlref.pod
    M pp.c
    M pp_proto.h
    M regen/opcodes
    M t/perf/opcount.t

  Log Message:
  -----------
  Add builtin:: funcs for handling weakrefs

Also, ensure that B::Deparse understands the OA_TARGMY optimisation of
OP_ISBOOL