[clang] [clang] Merge lifetimebound and GSL code paths for lifetime analysis (PR #104906)

[Haojian Wu via cfe-commits]

hokein wrote:

Reduced the libcxx failure to:

```
std::string_view test() {
  return std::move(*std::optional<std::string_view>());
}
```

We should not diagnose on this case. I think the PR https://github.com/llvm/llvm-project/pull/104556 should fix this.

https://github.com/llvm/llvm-project/pull/104906