Add some copy support for vulkan msaa

tools/gpu/GrTest.cpp

Index: tools/gpu/GrTest.cpp
diff --git a/tools/gpu/GrTest.cpp b/tools/gpu/GrTest.cpp
index d2c72956ea4152707e8df0361126b6ef23a3a051..aa4d78fd751a1f4c23eef8f6c8b4fb77d90c129b 100644
--- a/tools/gpu/GrTest.cpp
+++ b/tools/gpu/GrTest.cpp
@@ -306,7 +306,7 @@ public:
         *effectiveSampleCnt = rt->desc().fSampleCnt;
     }
 
-    bool initCopySurfaceDstDesc(const GrSurface* src, GrSurfaceDesc* desc) const override {
+    bool initCopySurfaceDstDesc(const GrRenderTarget* src, GrSurfaceDesc* desc) const override {
         return false;
     }