Change SkColor4f to RGBA channel order

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2093763003

Review-Url: https://codereview.chromium.org/2093763003
diff --git a/gm/color4f.cpp b/gm/color4f.cpp
index 5a516a5..b3be57b 100644
--- a/gm/color4f.cpp
+++ b/gm/color4f.cpp
@@ -99,10 +99,10 @@
     mat.set3x3(0, 1, 0, 0, 0, 1, 1, 0, 0);
 
     const SkColor4f colors[] {
-        { 1, 1, 0, 0 },
-        { 1, 0, 1, 0 },
         { 1, 0, 0, 1 },
-        { 1, 0.5, 0.5, 0.5 },
+        { 0, 1, 0, 1 },
+        { 0, 0, 1, 1 },
+        { 0.5, 0.5, 0.5, 1 },
     };
 
     SkPaint paint;