[lldb] Fix another instance where we pass a nullptr as TypeSourceInfo to NonTypeTemplateParmDecl::Create
Follow up to an issue pointed out in the review of D73808. We shouldn't just pass in a nullptr TypeSourceInfo
in case Clang decided to access it.
Reviewers: shafik, vsk
Reviewed By: shafik, vsk
Subscribers: kristof.beyls, JDevlieghere, lldb-commits
Differential Revision: https://reviews.llvm.org/D73946