https://dfinity.atlassian.net/browse/AST-53

In coverage.ml I am cutting corners, and reusing the infrastructure of plain products for labelled products, filling non-appearing field labels with wildcard patterns. I am interested to know whether you find this disgusting, I actually think it is cool. (I have changed nomenclature a bit to analyse products in general.)

Laundry list:

• refactor code parts which deal with pattern lists
• check whether there are simpler, more direct ways
• rename selectors, to avoid the necessity of disambiguation
• codegen
• suppress actor matches (for now); checking mode: done, inferring: not possible?
• suppress text, array matches this works now in frontend, codegen: done
• fix sort inference for shared func (other PR?, later)
• reject matching on mutable fields
• disable repeated pattern fields (dubious feature, no coverage yet); added better error message.