Minor GrRenderTarget retraction
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1967743003

Review-Url: https://codereview.chromium.org/1967743003
diff --git a/gm/texdata.cpp b/gm/texdata.cpp
index 977947b..494a932 100644
--- a/gm/texdata.cpp
+++ b/gm/texdata.cpp
@@ -69,9 +69,7 @@
         }
 
         GrSurfaceDesc desc;
-        // use RT flag bit because in GL it makes the texture be bottom-up
-        desc.fFlags     = i ? kRenderTarget_GrSurfaceFlag :
-                                kNone_GrSurfaceFlags;
+        desc.fOrigin    = i ? kBottomLeft_GrSurfaceOrigin : kTopLeft_GrSurfaceOrigin;
         desc.fConfig    = kSkia8888_GrPixelConfig;
         desc.fWidth     = 2 * S;
         desc.fHeight    = 2 * S;