[llvm] [BOLT][DWARF][NFC] Fix DebugStrOffsetsWriter (PR #100672)

[Alexander Yermolovich via llvm-commits]

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@@ -906,6 +906,7 @@ void DebugStrOffsetsWriter::finalizeSection(DWARFUnit &Unit,
   }
 
   StrOffsetSectionWasModified = false;
+  DebugStrOffsetFinalized[Unit.getOffset()] = true;
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ayermolo wrote:

see if this can be part of assert with .insert and checking output bool for if it's a new entry.
This way if asserts are disabled we don't have to insert anything in this.
You might need [[maybe_unused]] on definition so that clang doesn't report warnings if it not being used when asserts are disabled.

https://github.com/llvm/llvm-project/pull/100672