MAINT-7228 Vertex buffer allocation failure handling

indra/llrender/llvertexbuffer.cpp

indra/llrender/llvertexbuffer.h

indra/newview/lldrawpoolavatar.cpp

indra/newview/llfloaterimagepreview.cpp

indra/newview/llfloatermodelpreview.cpp

indra/newview/llspatialpartition.cpp

indra/newview/llvoavatar.cpp

indra/newview/llvoground.cpp

indra/newview/llvopartgroup.cpp

indra/newview/llvosky.cpp

indra/newview/llvotree.cpp

indra/newview/llvovolume.cpp

indra/newview/llvowater.cpp

indra/newview/llvowlsky.cpp

indra/newview/pipeline.cpp