[lldb] Ignore libcxx std::ranges global variables in frame var

The motivation is to avoid cluttering LLDB's global variable view for
std::ranges users.

Before:
```
(lldb) frame var -g
...
(const std::ranges::__end::__fn) std::__1::ranges::__cpo::end = {}
(const std::ranges::views::__all::__fn) std::__1::ranges::views::__cpo::all = {}
(const std::ranges::__begin::__fn) std::__1::ranges::__cpo::begin = {}
(const std::ranges::views::__take::__fn) std::__1::ranges::views::__cpo::take = {}
(const std::ranges::__max_element::__fn) std::__1::ranges::__cpo::max_element = {}
(const std::ranges::__size::__fn) std::__1::ranges::__cpo::size = {}
(const std::ranges::__data::__fn) std::__1::ranges::__cpo::data = {}
```

After this patch none of these __cpo variables would show up.

Differential Revision: https://reviews.llvm.org/D145245