[clang] [Serialization] Fix crash while lazy-loading template specializations (PR #150430)

[Jonas Hahnfeld via cfe-commits]

hahnjo wrote:

@michael-jabbour-sonarsource please have a look at https://llvm.org/docs//DeveloperPolicy.html#github-email-address, there is a "Keep my email addresses private" setting

https://github.com/llvm/llvm-project/pull/150430