[clang] [clang][NFC] Split invalid-cpu-note tests (PR #104601)

[Fangrui Song via cfe-commits]

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@@ -0,0 +1,90 @@
+// Use --implicit-check-not to ensure no additional CPUs are in this list
+
+// RUN: not %clang_cc1 -triple arm64--- -target-cpu not-a-cpu -fsyntax-only %s 2>&1 | FileCheck %s --implicit-check-not={{[a-zA-Z0-9]}}
+// RUN: not %clang_cc1 -triple arm64--- -tune-cpu not-a-cpu -fsyntax-only %s 2>&1 | FileCheck %s --implicit-check-not={{[a-zA-Z0-9]}}
+
+// CHECK: error: unknown target CPU 'not-a-cpu'
+// CHECK-NEXT: note: valid target CPU values are:
+// CHECK-SAME: a64fx,
----------------
MaskRay wrote:

Instead of having every CPU one the same line, you can group them by families like:
```
{{^}}, ampere1, ampere1a, ampere1b
{{^}}, fooX, fooY, fooZ
```

which still looks quite good.

Word diff tools are quite robust, so I think strictly avoiding packing is not necessary.

https://github.com/llvm/llvm-project/pull/104601