[clang-tools-extra] [clangd] Fix typeHierarchy/supertypes when a base is an implicit instantiation (PR #220240)

[Nathan Ridge via cfe-commits]

HighCommander4 wrote:

Can you evaluate for overlap with https://github.com/llvm/llvm-project/pull/177273?

https://github.com/llvm/llvm-project/pull/220240