[ORC] Preserve order of constructors with same priority

Constructors with the same priority should keep their relative order
that was specified. This is important for clang-repl with many const
variables after commit 05137ecfca ("[clang-repl] Emit const variables
only once").

---

Fixes #15511

(version of commit a60f353 for
LLVM 13 in v6-30-00-patches)

Author: hahnjo

interpreter/llvm-project/llvm-project.tag

@@ -1 +1 @@
-ROOT-llvm13-20240318-01
+ROOT-llvm13-20240614-01

interpreter/llvm-project/llvm/lib/ExecutionEngine/Orc/LLJIT.cpp

@@ -481,8 +481,8 @@ GlobalCtorDtorScraper::operator()(ThreadSafeModule TSM,
     std::vector<std::pair<Function *, unsigned>> Inits;
     for (auto E : getConstructors(M))
       Inits.push_back(std::make_pair(E.Func, E.Priority));
-    llvm::sort(Inits, [](const std::pair<Function *, unsigned> &LHS,
-                         const std::pair<Function *, unsigned> &RHS) {
+    llvm::stable_sort(Inits, [](const std::pair<Function *, unsigned> &LHS,
+                                const std::pair<Function *, unsigned> &RHS) {
       return LHS.second < RHS.second;
     });
     auto *EntryBlock = BasicBlock::Create(Ctx, "entry", InitFunc);