[clang] [C++20][Modules] Fix non-determinism in serialized AST (PR #110131)

[Dmitry Polukhin via cfe-commits]

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@@ -5713,8 +5713,7 @@ void ASTWriter::WriteDeclAndTypes(ASTContext &Context) {
     // efficent becuase it allows lazy deserialization.
     RecordData FunctionToLambdasMapRecord;
     for (const auto &Pair : FunctionToLambdasMap) {
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dmpolukhin wrote:

@rnk yes, the order is not important because we read the whole map into memory anyway. So IMHO the only thing we need to do here is to make sure that we order doesn't depend on pointer values. 

https://github.com/llvm/llvm-project/pull/110131