experiment: implicit-derivation-rep example of type reps failing inference

[crusso]

Part of reviewing #5966.

I thought this example (inferring a derived dictionary of functions( would work, but perhaps it's expected not to.

I guess we only apply inference if the hole has a function type - it can't be a record of methods. But is that restriction necessary?

I updated the review with some comments/questions

[github-actions]

Comparing from 9b961a3 to 1afa652:
The produced WebAssembly code seems to be completely unchanged.
In terms of gas, no changes are observed in 5 tests.
In terms of size, no changes are observed in 5 tests.

[Kamirus]

Answered here #5966 (comment)