Groom GHC.Builtin.Names for dead exports
I discovered that
groupWithName is exported but not used anywhere. Despite all the ongoing trickery surrounding known-key things, I think this binding could go, no?
The same probably applies to a couple of other Names in there. Maybe a tool like
weeder would find out. I think we even tried that in #17713, but I couldn't find
groupWithName in any of the mentions there.
Other dead NAmes: