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/tests/Float16Test.cpp b/tests/Float16Test.cpp
index 6a7f984..d80fe29 100644
--- a/tests/Float16Test.cpp
+++ b/tests/Float16Test.cpp
@@ -43,7 +43,7 @@
     pm.alloc(info);
     REPORTER_ASSERT(reporter, pm.getSafeSize() == SkToSizeT(w * h * sizeof(uint64_t)));
 
-    SkColor4f c4 { 0.5f, 1, 0.5f, 0.25f };
+    SkColor4f c4 { 1, 0.5f, 0.25f, 0.5f };
     pm.erase(c4);
 
     SkPM4f origpm4 = c4.premul();