[clang] [clang][Driver][Darwin] Optionally use xcselect to find macOS SDK (PR #119670)

[Carlo Cabrera via cfe-commits]

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@@ -43,8 +43,8 @@
 
 // RUN: %clang -target x86_64-apple-macos10.13 -mlinker-version=520 \
 // RUN:   -### %t.o 2>&1 \
-// RUN:   | FileCheck --check-prefix=NOSDK %s
+// RUN:   | FileCheck --check-prefix=INFERRED-SDK %s
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carlocab wrote:

I think they'll pass since I've just relaxed the text to match against. But I'll double check locally for both enabling and disabling `CLANG_USE_XCSELECT` and delete them if it fails.

https://github.com/llvm/llvm-project/pull/119670