[OpenMP][FIX] Ensure flag to disable de-globalization works properly

[jdoerfert]

Summary

If the user disables de-globalization we did not seed the AAHeapToShared
and AAHeapToStack but we still could end up with them through in-flight
lookups. With this patch we disable AAHeapToShared completely if the
user disabled de-globalization. Heap-2-stack is still run though.

[jhuber6]

LG

llvm/lib/Transforms/IPO/OpenMPOpt.cpp

for (CallBase *CB : MallocCalls) {
       if (FreeCalls.size() != 1)
         continue;
 
       PotentialRemovedFreeCalls.insert(FreeCalls.front());
     }
   }
 
   void initialize(Attributor &A) override {
+    if (DisableOpenMPOptDeglobalization) {
+      indicatePessimisticFixpoint();
+      return;
+    }
+
     auto &OMPInfoCache = static_cast<OMPInformationCache &>(A.getInfoCache());
     auto &RFI = OMPInfoCache.RFIs[OMPRTL___kmpc_alloc_shared];
 
     Attributor::SimplifictionCallbackTy SCB =
         [](const IRPosition &, const AbstractAttribute *,
            bool &) -> Optional<Value *> { return nullptr; };
     for (User *U : RFI.Declaration->users())
       if (CallBase *CB = dyn_cast<CallBase>(U)) {