[clang] [clang-repl] Implement LoadDynamicLibrary for clang-repl wasm use cases (PR #133037)

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llvmbot wrote:

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Failed to cherry-pick: [8f56394](https://github.com/llvm/llvm-project/commit/8f56394487a4d454be0637667267ad37bd636d0f)

https://github.com/llvm/llvm-project/actions/runs/14705684610

Please manually backport the fix and push it to your github fork.  Once this is done, please create a [pull request](https://github.com/llvm/llvm-project/compare)

https://github.com/llvm/llvm-project/pull/133037