widen output png size of bmp_filter_quality_repeat

BUG=skia:

Review URL: https://codereview.chromium.org/1097443002
diff --git a/gm/bmpfilterqualityrepeat.cpp b/gm/bmpfilterqualityrepeat.cpp
index f533860..1097141 100644
--- a/gm/bmpfilterqualityrepeat.cpp
+++ b/gm/bmpfilterqualityrepeat.cpp
@@ -35,7 +35,7 @@
 
     SkString onShortName() override { return SkString("bmp_filter_quality_repeat"); }
 
-    SkISize onISize() override { return SkISize::Make(810, 235); }
+    SkISize onISize() override { return SkISize::Make(1000, 235); }
 
     void onDraw(SkCanvas* canvas) override {