Render Movie using separate process crashes capture process

This is a regression exposed at CL 3242934 - QAGame: Adding test content to QA-Sequencer for Override Bindings.

Crash does not occur in 4.16.

I'm not certain how the content changes are triggering this crash, but at least it's a starting place.

1. Open QAGame in the Editor
2. Open the map QA-Sequencer
3. Navigate to Cinematics > MasterSequence and click it to open it in Sequencer
4. Click the Render to Movie button in Sequencer
5. In the dialogue that opens, expand the Advanced Options of the General section and enable Use Separate Process
6. Click Capture Movie

Result: Observe that the separate editor rendering out the movie crashes on starting up

Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 633] Array index out of bounds: 0 from an array of size 0

UE4Editor_AnimGraphRuntime!FAnimNode_MultiWayBlend::Evaluate() animnode_multiwayblend.cpp:114
UE4Editor_Engine!FPoseLink::Evaluate() animnodebase.cpp:221
UE4Editor_AnimGraphRuntime!FAnimNode_ApplyAdditive::Evaluate() animnode_applyadditive.cpp:58
UE4Editor_AnimGraphRuntime!FAnimSequencerInstanceProxy::Evaluate() animsequencerinstanceproxy.cpp:16
UE4Editor_Engine!FAnimInstanceProxy::EvaluateAnimation() animinstanceproxy.cpp:837
UE4Editor_Engine!UAnimInstance::ParallelEvaluateAnimation() animinstance.cpp:531
UE4Editor_Engine!USkeletalMeshComponent::EvaluateAnimation() skeletalmeshcomponent.cpp:1403
UE4Editor_Engine!USkeletalMeshComponent::PerformAnimationEvaluation() skeletalmeshcomponent.cpp:1481
UE4Editor_Engine!USkeletalMeshComponent::RefreshBoneTransforms() skeletalmeshcomponent.cpp:1689
UE4Editor_Engine!USkeletalMeshComponent::InitAnim() skeletalmeshcomponent.cpp:530
UE4Editor_Engine!AActor::InitializeComponents() actor.cpp:4174
UE4Editor_Engine!ULevel::RouteActorInitialize() level.cpp:1740
UE4Editor_Engine!UWorld::InitializeActorsForPlay() world.cpp:3351
UE4Editor_Engine!UEngine::LoadMap() unrealengine.cpp:10189
UE4Editor_Engine!UEngine::Browse() unrealengine.cpp:9492
UE4Editor_Engine!UGameInstance::StartGameInstance() gameinstance.cpp:416
UE4Editor!FEngineLoop::Init() launchengineloop.cpp:2538
UE4Editor!GuardedMain() launch.cpp:153
UE4Editor!GuardedMainWrapper() launchwindows.cpp:134
UE4Editor!WinMain() launchwindows.cpp:210
UE4Editor!__scrt_common_main_seh() exe_common.inl:264
kernel32!<Unknown>
ntdll!<Unknown>