[llvm] [llvm-profgen] Improve sample profile density (PR #92144)

[via llvm-commits]

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@@ -121,7 +121,7 @@ class ProfileGeneratorBase {
   double calculateDensity(const SampleProfileMap &Profiles,
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WenleiHe wrote:

If we change how density is calculated, we should change it everywhere to be consistent. Why leaving the old heuristic there for non-CS profile? 

https://github.com/llvm/llvm-project/pull/92144