GPU Crash may occur when using Nanite Tesselation on landscape with several shadow casting local lights

The GPU may time out in NaniteSplit when drawing VSM shadows for Nanite Tessellated landscape with in a scene with several local shadowed point lights. The issue doesn't reproduce in 5.6, likely to the refactoring of NaniteSplit. Related CLs:

CL#37563978 Converted Nanite patch split to multi-pass.

CL#37869798 Fixed issue where tessellation has missing triangles when getting too close.

1. Run GPUCrash.uproject
2. Fly around the map until you get GPU Crash.

Device 0, Pipeline Graphics: (In: 0x800b7553, Out: 0x800b7553)
[     Active]    Frame 2920
[     Active]    FRDGBuilder::Execute
[     Active]        Scene
[     Active]            ShadowDepths
[     Active]                RenderVirtualShadowMaps(Nanite)
[     Active]                    Nanite::DrawGeometry
[   Finished]                        MainPass
[   Finished]                            NodeAndClusterCull
[   Finished]                        BuildPreviousOccluderHZB(VSM)
[     Active]                        PostPass
[     Active]                            NodeAndClusterCull
[Not Started]                RenderVirtualShadowMaps(Non-Nanite)
[Not Started]                FVirtualShadowMapArray::MergeStaticPhysicalPages
[Not Started]            Nanite::Readback
[Not Started]            RenderDeferredLighting