[llvm] [llvm-exegesis] Add tablegen support for validation counters (PR #76652)

[Clement Courbet via llvm-commits]

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@@ -28,6 +28,27 @@ class PfmIssueCounter<string resource_name, string counter>
   string ResourceName = resource_name;
 }
 
+// Definition of a validation event. A validation event represents a specific
+// event that can be meaasured using performance counters that is interesting
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legrosbuffle wrote:

typo: meaasured

https://github.com/llvm/llvm-project/pull/76652