[clang] [Sema] Fix lifetime extension for temporaries in range-based for loops in C++23 (PR #145164)

[Haojian Wu via cfe-commits]

================
@@ -1341,6 +1341,14 @@ checkExprLifetimeImpl(Sema &SemaRef, const InitializedEntity *InitEntity,
       }
 
       if (IsGslPtrValueFromGslTempOwner && DiagLoc.isValid()) {
+
+        if (SemaRef.getLangOpts().CPlusPlus23) {
----------------
hokein wrote:

the analysis is done here, and we filter out the result. I think we can filter out this case before (in `checkExprLifetimeImpl`) running the analysis to save some cost. 

Can you add a testcase (for the `lifetimebound` attr)? Make sure we don't warn on it

```
using size_t = decltype(sizeof(void *));

namespace my_ns {
template <typename T> struct vector {
  T &operator[](size_t I) [[clang::lifetimebound]];
};

struct string {
  const char *begin();
  const char *end();
};

} // namespace std

my_ns::vector<my_ns::string> getData();

void foo() {

  for (auto c : getData()[0]) {
    (void)c;
  }
}
```

https://github.com/llvm/llvm-project/pull/145164