Fix copying of data in vulkan testing texture

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2248703002

Review-Url: https://codereview.chromium.org/2248703002
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index e238911..06c27ea 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -655,7 +655,7 @@
 }
 
 sk_sp<GrDrawContext> GrContextPriv::makeBackendTextureAsRenderTargetDrawContext(
-                                                     const GrBackendTextureDesc& desc, 
+                                                     const GrBackendTextureDesc& desc,
                                                      sk_sp<SkColorSpace> colorSpace,
                                                      const SkSurfaceProps* surfaceProps) {
     ASSERT_SINGLE_OWNER_PRIV