gm/gammagradienttext: Attempt to see what changed in gold.

Change-Id: Ic2ac8d9a17338e9c0deefcb28bebe1853f74704f
Reviewed-on: https://skia-review.googlesource.com/c/182221
Auto-Submit: Hal Canary <halcanary@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>

gm/gammatext.cpp

@@ -137,6 +137,7 @@ protected:
 
     void onDraw(SkCanvas* canvas) override {
         SkPaint paint;
+        paint.setAntiAlias(true);
         SkFont font(SkTypeface::MakeFromName("serif", SkFontStyle::Italic()), 18);
         font.setEdging(SkFont::Edging::kSubpixelAntiAlias);