[llvm] [memprof] Group MemProf data structures into a struct (NFC) (PR #92360)

[Teresa Johnson via llvm-commits]

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@@ -603,23 +592,17 @@ static Error writeMemProfV2(
 // uint64_t Schema entry N - 1
 // OnDiskChainedHashTable MemProfRecordData
 // OnDiskChainedHashTable MemProfFrameData
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teresajohnson wrote:

As a side note, does this description need to be updated to add the MemProfCallStackData?

https://github.com/llvm/llvm-project/pull/92360