add guard for android (needs rebaseline)

android.graphics.drawable.cts.BitmapDrawableTest.testPreloadDensity(BitmapDrawableTest.java:556)

Bug: skia:
Change-Id: Ibc6b67c6ec82f578ffffd7461e2505713c704b8d
Reviewed-on: https://skia-review.googlesource.com/21824
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
1 file changed