[io grant] Test IO::CatHandle.Supply
[io grant] Test IO::CatHandle.Supply

8 tests are fudged due to newly discovered IO::Handle.readchars bug:
https://rt.perl.org/Ticket/Display.html?id=131383

dogbert17/roast,dogbert17/roast,perl6/roast,bitrauser/roast,bitrauser/roast