Revert "[Clang] Unify interface for accessing template arguments as written for class/variable template specializations (#81642)"

This reverts commit 7115ed0fff027b65fa76fdfae215ed1382ed1473.

This commit broke several LLDB tests.

https://green.lab.llvm.org/job/llvm.org/view/LLDB/job/as-lldb-cmake/3480/

GitOrigin-RevId: c6855ab24e63feb432aac4f86eb70ac16d76c921
3 files changed