[clang] Mark tests as unsupported when targeting z/OS (PR #107916)

[Sean Perry via cfe-commits]

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@@ -24,6 +24,7 @@
 //
 // FIXME: Path handling should work on all platforms.
 // REQUIRES: system-linux
+// UNSUPPORTED: target={{.*}}-zos{{.*}}
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perry-ca wrote:

Unless we can prove that is the case, it is better to stick with the more selective condition.  I don't think many people run lit cross target so it would be difficult to validate.

https://github.com/llvm/llvm-project/pull/107916