Fix named arguments in super and previous_def calls

[HertzDevil]

Fixes #8895 (including the examples in the comment).

Specifically, this PR

• No longer considers super / previous_def expansion if a call uses only named arguments but no positional arguments.
• Drops the bare splat parameter in the expanded call. (This is what triggers the local variable '' part.)
• Implicitly forwards also the double splat parameter, if one exists.
• Ensures named parameters in the enclosing def are implicitly forwarded always by their external names, not internal ones.

[asterite]

Awesome! 💜