[libunwind] [libunwind] fix pc range condition check bug (PR #154902)

[Wu Yingcong via cfe-commits]

yingcong-wu wrote:

For stage3 (bootstrapping-build, llvm-premerge-libcxx-next-runners), I don't think the failure is related to my change.

```
  Unresolved Tests (2):
    lldb-api :: functionalities/data-formatter/data-formatter-stl/generic/list/TestDataFormatterGenericList.py
    lldb-api :: functionalities/data-formatter/data-formatter-stl/generic/list/loop/TestDataFormatterGenericListLoop.py
  
  ********************
  Failed Tests (1):
    lldb-api :: functionalities/data-formatter/data-formatter-stl/generic/forward_list/TestDataFormatterGenericForwardList.py
```

As for the buildkite failures, I don't have a clue, but it should not relate to this change either. I see this from the log
```
ninja: error: unknown target 'check-cxx-abilist'
  | + error 'Generating the libc++ ABI list after failed check'
  | + echo '::error::Generating the libc++ ABI list after failed check'
```

https://github.com/llvm/llvm-project/pull/154902