Refactor how we store and use samplers in Ganesh

src/gpu/vk/GrVkPipelineStateDataManager.h

Index: src/gpu/vk/GrVkPipelineStateDataManager.h
diff --git a/src/gpu/vk/GrVkPipelineStateDataManager.h b/src/gpu/vk/GrVkPipelineStateDataManager.h
index 089d170f124f5c90e358c8d058137d88dc3e5a1a..0a035799b62e02ea760f3a2b094af09efa81b268 100644
--- a/src/gpu/vk/GrVkPipelineStateDataManager.h
+++ b/src/gpu/vk/GrVkPipelineStateDataManager.h
@@ -59,7 +59,6 @@ private:
         SkDEBUGCODE(
             GrSLType    fType;
             int         fArrayCount;
-            uint32_t    fSetNumber;
         );
     };