[llvm-branch-commits] [sanitizer] Rename DEFINE_REAL_PTHREAD_FUNCTIONS (PR #96527)

[Vitaly Buka via llvm-branch-commits]

https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/96527

We use REAL() calls in interceptors, but
DEFINE_REAL_PTHREAD_FUNCTIONS has nothing to do
with them and only used for internal maintenance
threads.