[ASL] Allow multiple access to record fields and other features

[HadrienRenaud]

This PR brings the following features:

• [x] Allow multiple read to record fields, if those are of bitvector type.
• [x] Allow multiple write to record fields, if those are of bitvector type.
• [x] Change from the DEBUG syntax for the reserved __debug__ one
• [x] Some improvments to ASLRefs' commandline interface
• [x] Fixes topological sorting of patterns
• [x] Fixes some problems with parametric return types
• [x] Fixes some too eager named-type erasure

[maranget]

Hi @HadrienRenaud, LGTM. I have made a few remarks, most of which are questions.

[HadrienRenaud]

Thank you @maranget for the feedback I'm going to merge 🙂