Send SkDebugf through stderr and flush on Windows too.

src/ports/SkDebug_win.cpp

Index: src/ports/SkDebug_win.cpp
diff --git a/src/ports/SkDebug_win.cpp b/src/ports/SkDebug_win.cpp
index 8bbbef58e09d39cc60ca02df5f819426d1c5a604..ed706c1d7b83cc83708cdaa386534f12c4222fa8 100644
--- a/src/ports/SkDebug_win.cpp
+++ b/src/ports/SkDebug_win.cpp
@@ -21,11 +21,9 @@ void SkDebugf(const char format[], ...) {
     va_list args;
 
     va_start(args, format);
-    vprintf(format, args);
+    vfprintf(stderr, format, args);
     va_end(args);
-    // When we crash on Windows we often are missing a lot of prints. Since we don't really care
-    // about SkDebugf performance we flush after every print.
-//    fflush(stdout);
+    fflush(stderr);
 
     va_start(args, format);
     vsnprintf(buffer, kBufferSize, format, args);