[compiler-rt] [sanitizer] Fix asserts in asan and tsan in pthread interceptors. (PR #75394)

[Vitaly Buka via llvm-commits]

================
@@ -23,6 +23,9 @@ void ThreadArgRetval::CreateLocked(uptr thread, bool detached,
   Data& t = data_[thread];
   t = {};
   t.gen = gen_++;
+  static_assert(sizeof(gen_) == sizeof(u32) && kInvalidGen == UINT32_MAX);
+  if (gen_ == kInvalidGen)
----------------
vitalybuka wrote:

I guess I missed `if (gen_ == kInvalidGen) = 0`,
so we don't need the one introduced with https://github.com/llvm/llvm-project/pull/75394/commits/b96deb8525d6ca6d94bcf99d808b1912be1f8068

https://github.com/llvm/llvm-project/pull/75394