Editor Crashes When Reloading Textures in Debug Tools

Crash occurs while Playing in Editor and debugging by reloading textures. Occurs for both Mac and PC.

Regression: Does not occur in UE4.10 testing on Match 3

Steps to reproduce:

1. Open Match 3 on 4.11.1
2. Press Play (in Editor)
3. From top menu, go to Window->Developer Tools -> Debug Tools
4. Press Reload Textures

UE4Editor_Core!scalable_msize() frontend.cpp:2615
UE4Editor_Core!FMallocTBB::Realloc() malloctbb.cpp:70
UE4Editor_Core!FHeapAllocator::ForAnyElementType::ResizeAllocation() containerallocationpolicies.h:357
UE4Editor_SlateRHIRenderer!TInlineAllocator<4,FDefaultAllocator>::ForElementType<unsigned int>::ResizeAllocation() containerallocationpolicies.h:482
UE4Editor_SlateRHIRenderer!TSparseArray<TSetElement<UObject * __ptr64>,TSparseArrayAllocator<FDefaultAllocator,FDefaultBitArrayAllocator> >::Empty() sparsearray.h:230
UE4Editor_SlateRHIRenderer!FSlateRHIResourceManager::GetAccessedUObjects() slaterhiresourcemanager.cpp:868
UE4Editor_SlateRHIRenderer!FSlateRHIResourceManager::FindOrCreateDynamicTextureResource() slaterhiresourcemanager.cpp:664
UE4Editor_SlateRHIRenderer!FSlateRHIResourceManager::GetShaderResource() slaterhiresourcemanager.cpp:500
UE4Editor_SlateCore!FSlateDrawElement::MakeBox() drawelements.cpp:82
UE4Editor_Slate!SButton::OnPaint() sbutton.cpp:82
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SCompoundWidget::OnPaint() scompoundwidget.cpp:25
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SOverlay::OnPaint() soverlay.cpp:100
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SCompoundWidget::OnPaint() scompoundwidget.cpp:25
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SPanel::PaintArrangedChildren() spanel.cpp:44
UE4Editor_SlateCore!SPanel::OnPaint() spanel.cpp:19
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SPanel::PaintArrangedChildren() spanel.cpp:44
UE4Editor_SlateCore!SPanel::OnPaint() spanel.cpp:19
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SCompoundWidget::OnPaint() scompoundwidget.cpp:25
UE4Editor_UMG!SObjectWidget::OnPaint() sobjectwidget.cpp:71
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_Slate!SConstraintCanvas::OnPaint() sconstraintcanvas.cpp:192
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SOverlay::OnPaint() soverlay.cpp:100
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SOverlay::OnPaint() soverlay.cpp:100
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SPanel::PaintArrangedChildren() spanel.cpp:44
UE4Editor_SlateCore!SPanel::OnPaint() spanel.cpp:19
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_Slate!SScissorRectBox::OnPaint() sscissorrectbox.cpp:66
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SCompoundWidget::OnPaint() scompoundwidget.cpp:25
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SOverlay::OnPaint() soverlay.cpp:100
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SCompoundWidget::OnPaint() scompoundwidget.cpp:25
UE4Editor_Slate!SViewport::OnPaint() sviewport.cpp:114
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SCompoundWidget::OnPaint() scompoundwidget.cpp:25
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_Slate!SCanvas::OnPaint() scanvas.cpp:116
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SOverlay::OnPaint() soverlay.cpp:100
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SCompoundWidget::OnPaint() scompoundwidget.cpp:25
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SCompoundWidget::OnPaint() scompoundwidget.cpp:25
UE4Editor_Slate!SBorder::OnPaint() sborder.cpp:90
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SOverlay::OnPaint() soverlay.cpp:100
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SPanel::PaintArrangedChildren() spanel.cpp:44
UE4Editor_SlateCore!SPanel::OnPaint() spanel.cpp:19
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SCompoundWidget::OnPaint() scompoundwidget.cpp:25
UE4Editor_SlateCore!SWidget::Paint() swidget.cpp:669
UE4Editor_SlateCore!SPanel::PaintArrangedChildren() spanel.cpp:44
UE4Editor_Slate!SSplitter::OnPaint() ssplitter.cpp:166