[clang] [clang][nfc] Guard thread_local in clang/test/CXX/drs/cwg7xx.cpp (PR #197930)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

> I believe Clang behavior is incorrect, and I'll file a dedicated issue for that, because it's a rabbit's hole.

#198089

https://github.com/llvm/llvm-project/pull/197930