Verify performance of type.newSupertypeHierarchy API

[bensonnw]

Description:

In AbstractDiagnosticsCollector class, we are using type.newSupertypeHierarchy API to get full hierarchy of the Java class, we probably need to verify its performance to make sure it's not too expensive, otherwise, we may have to use some other ways.

Specification:

Type of language feature proposed:

Select all that apply

• [x] diagnostic
• [ ] quick-fix
• [ ] snippet
• [ ] other, please specify: