[ fix ] Remove type constructor tags

[spcfox]

Description

Currently, the type constructor tag is always 100. In fact, they are not used. Therefore, I propose to remove them and also fix several related bugs.

Commits:

1. Fixed a bug that prevented the tag counter from increasing
2. Fixed irrefutable pattern with type in index
3. Fixed checking for emptiness of type with type in index. This is the only place where type constructors are compared by tags. But they are unique only within the module. Therefore, type constructors should be compared by name, as in all other places.
4. Type constructor tags have been removed because they are not suitable for comparison and are no longer used.
5. Remove some boilerplate.

Should this change go in the CHANGELOG?

• If this is a fix, user-facing change, a compiler change, or a new paper
  implementation, I have updated CHANGELOG_NEXT.md (and potentially also
  CONTRIBUTORS.md).

[spcfox]

Also, tags removed in Yaffle
edwinb/Yaffle@f26c9a0#diff-ba25068d28a398c3bade02a547922670d11ca8845d0e54a9ed9b180e9d76b702