[libunwind] libunwind: Remove OS requirements from tests to make them run on more OSes (PR #167642)

[Alexander Richardson via cfe-commits]

================
@@ -13,15 +13,15 @@
 
 // clang-format off
 
-// REQUIRES: target={{x86_64-.+-linux-gnu}}
+// REQUIRES: target-x86_64
----------------
arichardson wrote:

```suggestion
// REQUIRES: target={{x86_64-.+}}
```

https://github.com/llvm/llvm-project/pull/167642