Crash on ParticleSystemUpdateData::CacheSubEmitters(ParticleSystem&) when shared subemitter referenced by multiple nested particle systems

Steps to reproduce:

1. Import the attached package
2. Enabled Root Gameobject
3. Click on PSSharedLeaf GameObjects
4. Observe that the Editor crashed

Reproducible with versions: 6000.6.0a5, 6000.5.0b8, 6000.3.6f1, 6000.0.75f1

Not reproducible with versions: 6000.0.76f1 (fixed)

Can’t test with versions: n/a

Tested on (OS): macOS

Callstack:
#0 0x0000010393d66e in ParticleSystem::AllocateParticleArrays()
#1 0x000001038bd121 in ParticleSystemUpdateData::CacheSubEmitters(ParticleSystem&)
#2 0x000001039351c1 in ParticleSystem::Update1a(ParticleSystemUpdateData&)
#3 0x000001039478a0 in ParticleSystem::CollectSubEmittersRecursive(ParticleSystemUpdateData*, core::vector<ParticleSystem::UpdateOrderData, core::allocator<ParticleSystem::UpdateOrderData, 0ul>>&, float, float, int)
#4 0x000001039478d9 in ParticleSystem::CollectSubEmittersRecursive(ParticleSystemUpdateData*, core::vector<ParticleSystem::UpdateOrderData, core::allocator<ParticleSystem::UpdateOrderData, 0ul>>&, float, float, int)
#5 0x00000103946ca6 in ParticleSystem::JobsSchedulerHelper::ScheduleUpdateJobsHelper(core::vector<ParticleSystem::UpdateOrderData, core::allocator<ParticleSystem::UpdateOrderData, 0ul>>&, core::vector<JobFence*, core::allocator<JobFence*, 0ul>>&, double, float, float, JobBatchDispatcher&)
#6 0x0000010393cc3e in ParticleSystem::BeginUpdate(ParticleSystem**, unsigned long, float, float)
#7 0x0000010392fc27 in ParticleSystem::BeginUpdateAll()
#8 0x00000103930b87 in ParticleSystem::InitializeClass()::PreLateUpdateParticleSystemBeginUpdateAllRegistrator::Forward()
#9 0x00000102ca9540 in ExecutePlayerLoop(NativePlayerLoopSystem*)
#10 0x00000102ca9581 in ExecutePlayerLoop(NativePlayerLoopSystem*)