make tests portable by using 565 compatible colors

TBR=reed@google.com

Review URL: https://codereview.chromium.org/1262703002
diff --git a/gm/rrect.cpp b/gm/rrect.cpp
index 4c55654..5106634 100644
--- a/gm/rrect.cpp
+++ b/gm/rrect.cpp
@@ -104,7 +104,7 @@
     if (rrect.isRect()) {
         paint.setColor(SK_ColorRED);
     } else if (rrect.isOval()) {
-        paint.setColor(0xFF008800);
+        paint.setColor(sk_tool_utils::color_to_565(0xFF008800));
     } else if (rrect.isSimple()) {
         paint.setColor(SK_ColorBLUE);
     } else {