[lldb] Also set owning module for template specializations

Summary:
This was originally commented out as it broke the data-formatter-stl/libcxx/
tests. However this was fixed by commit ef423a3b
(Add Objective-C property accessors loaded from Clang module DWARF to lookup)
which sets the HasExternalVisibleStorage flag for the template specializations.

Reviewers: aprantl

Reviewed By: aprantl

Subscribers: abidh, JDevlieghere

Differential Revision: https://reviews.llvm.org/D79168