Revert "[ORC] Enable JITEventListeners in the RTDyldObjectLinkingLayer."

This reverts commit 98f2bb4461072347dcca7d2b1b9571b3a6525801.

Reverting while I investigate bot failures.
diff --git a/llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp b/llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp
index 3fafe4a..f51bd9d 100644
--- a/llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp
@@ -81,12 +81,8 @@
 
 RTDyldObjectLinkingLayer::~RTDyldObjectLinkingLayer() {
   std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
-  for (auto &MemMgr : MemMgrs) {
-    for (auto *L : EventListeners)
-      L->notifyFreeingObject(
-          static_cast<uint64_t>(reinterpret_cast<uintptr_t>(MemMgr.get())));
+  for (auto &MemMgr : MemMgrs)
     MemMgr->deregisterEHFrames();
-  }
 }
 
 void RTDyldObjectLinkingLayer::emit(MaterializationResponsibility R,
@@ -159,35 +155,19 @@
 
   jitLinkForORC(
       **Obj, std::move(O), *MemMgr, Resolver, ProcessAllSections,
-      [this, K, SharedR, &Obj, MemMgr, InternalSymbols](
+      [this, K, SharedR, &Obj, InternalSymbols](
           std::unique_ptr<RuntimeDyld::LoadedObjectInfo> LoadedObjInfo,
           std::map<StringRef, JITEvaluatedSymbol> ResolvedSymbols) {
-        return onObjLoad(K, *SharedR, **Obj, MemMgr, std::move(LoadedObjInfo),
+        return onObjLoad(K, *SharedR, **Obj, std::move(LoadedObjInfo),
                          ResolvedSymbols, *InternalSymbols);
       },
-      [this, K, SharedR, &Obj, O = std::move(O), MemMgr](Error Err) mutable {
-        onObjEmit(K, *SharedR, **Obj, std::move(O), MemMgr, std::move(Err));
+      [this, K, SharedR, O = std::move(O)](Error Err) mutable {
+        onObjEmit(K, std::move(O), *SharedR, std::move(Err));
       });
 }
 
-void RTDyldObjectLinkingLayer::registerJITEventListener(JITEventListener &L) {
-  std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
-  assert(llvm::none_of(EventListeners,
-                       [&](JITEventListener *O) { return O == &L; }) &&
-         "Listener has already been registered");
-  EventListeners.push_back(&L);
-}
-
-void RTDyldObjectLinkingLayer::unregisterJITEventListener(JITEventListener &L) {
-  std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
-  auto I = llvm::find(EventListeners, &L);
-  assert(I != EventListeners.end() && "Listener not registered");
-  EventListeners.erase(I);
-}
-
 Error RTDyldObjectLinkingLayer::onObjLoad(
     VModuleKey K, MaterializationResponsibility &R, object::ObjectFile &Obj,
-    RuntimeDyld::MemoryManager *MemMgr,
     std::unique_ptr<RuntimeDyld::LoadedObjectInfo> LoadedObjInfo,
     std::map<StringRef, JITEvaluatedSymbol> Resolved,
     std::set<StringRef> &InternalSymbols) {
@@ -272,17 +252,12 @@
   if (NotifyLoaded)
     NotifyLoaded(K, Obj, *LoadedObjInfo);
 
-  std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
-  assert(!LoadedObjInfos.count(MemMgr) && "Duplicate loaded info for MemMgr");
-  LoadedObjInfos[MemMgr] = std::move(LoadedObjInfo);
-
   return Error::success();
 }
 
 void RTDyldObjectLinkingLayer::onObjEmit(
-    VModuleKey K, MaterializationResponsibility &R, object::ObjectFile &Obj,
-    std::unique_ptr<MemoryBuffer> ObjBuffer, RuntimeDyld::MemoryManager *MemMgr,
-    Error Err) {
+    VModuleKey K, std::unique_ptr<MemoryBuffer> ObjBuffer,
+    MaterializationResponsibility &R, Error Err) {
   if (Err) {
     getExecutionSession().reportError(std::move(Err));
     R.failMaterialization();
@@ -297,16 +272,6 @@
 
   if (NotifyEmitted)
     NotifyEmitted(K, std::move(ObjBuffer));
-
-  // Run EventListener notifyLoaded callbacks.
-  std::lock_guard<std::mutex> Lock(RTDyldLayerMutex);
-  auto LOIItr = LoadedObjInfos.find(MemMgr);
-  assert(LOIItr != LoadedObjInfos.end() && "LoadedObjInfo missing");
-  for (auto *L : EventListeners)
-    L->notifyObjectLoaded(
-        static_cast<uint64_t>(reinterpret_cast<uintptr_t>(MemMgr)), Obj,
-        *LOIItr->second);
-  LoadedObjInfos.erase(MemMgr);
 }
 
 LegacyRTDyldObjectLinkingLayer::LegacyRTDyldObjectLinkingLayer(