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

[Abhina Sree 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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abhina-sree wrote:

Would this work instead? I think this testcase won't work for all non-linux targets

// REQUIRES: system-linux && target={{.*linux.*}}

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