swift234

Further shorten demangled names in simplified mode

Break up "Simplified" demangling mode (shortened demangled descriptions
for the sake of displaying in UI with small areas) into more
fine-grained options instead of an opaque "Simplified" option and
provide a static preset of options for displaying stack traces in
Xcode UI and other tools, for example.

- Don't print unmangled suffixes
- Don't print module names
- Shorten various generic specialization descriptions as just
  "specialized"
- Don't display long protocol conformances
- Truncate where clauses
- Don't display so-called "entity" types
- Shorten "partial apply *"
- Shorten thunk phrases
- Shorten value witness phrases
- Truncate archetype references

rdar://problem/21753651

Swift SVN r30247