Initialize ShadowImageView.matrix field to prevent NPE. Real android source starts with this field initialized:-

https://android.googlesource.com/platform/frameworks/base/+/jb-release/core/java/android/widget/ImageView.java
Add test for ImageView to show that ImageView.matrix must be initialized
Merge branch 'master' of https://github.com/robolectric/robolectric into shadow_image_view_fix
Merge pull request #1271 from jongerrish/shadow_image_view_fix

Initialize ShadowImageView.matrix field to prevent NPE.