Make sure the VirtualSwapchain layer is loaded only once in a replay (#3180)
Make sure the VirtualSwapchain layer is loaded only once in a replay (#3180)

Gapir systematically loads the VirtualSwapchain layer as the last
layer. A trace may list the VirtualSwapchain layer as a required
layer (e.g., the trace of a replay would.) To avoid loading the
VirtualSwapchain layer twice, we remove it from the list of layers
requested by the trace.
google/agi,google/gapid,google/agi,google/gapid,pmuetschard/gapid,google/gapid,google/gapid,pmuetschard/gapid,pmuetschard/gapid,google/gapid,pmuetschard/gapid,pmuetschard/gapid,pmuetschard/gapid,google/agi,google/gapid,google/gapid,google/agi,google/gapid,google/agi,google/agi,pmuetschard/gapid,pmuetschard/gapid,google/agi,google/agi