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

[Wu Yingcong via cfe-commits]

yingcong-wu wrote:

As this test result shows, the test case also fails without my change to libunwind: https://github.com/llvm/llvm-project/actions/runs/17313128556/job/49152917070?pr=154902 (head is be13b4d8).
```
  # .---command stderr------------
  # | MemorySanitizer:DEADLYSIGNAL
  # | ==1153229==ERROR: MemorySanitizer: stack-overflow on address 0x7ffc3702ea78 (pc 0x560f4f3e9257 bp 0x7ffc3702f2c0 sp 0x7ffc3702ea80 T1153229)
  # | MemorySanitizer:DEADLYSIGNAL
  # | MemorySanitizer: nested bug in the same thread, aborting.
  # `-----------------------------
```

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