Disable WritePixelsTest on Android

This fails on Xoom.  Re-enable when #634 is fixed.
Review URL: https://codereview.appspot.com/6354099

git-svn-id: http://skia.googlecode.com/svn/trunk@4584 2bbb7eff-a529-9590-31e7-b0007b416f81

tests/WritePixelsTest.cpp

@@ -415,6 +415,7 @@ void WritePixelsTest(skiatest::Reporter* reporter, GrContext* context) {
 }
 }
 
+#ifndef SK_BUILD_FOR_ANDROID
 #include "TestClassDef.h"
 DEFINE_GPUTESTCLASS("WritePixels", WritePixelsTestClass, WritePixelsTest)
-
+#endif