Add a JNI library for CtsUiRenderingTestCases

Bug: 160984428
Test: this

This will allow testing NDK APIs in the uirendering package. This
follows the general trend of adding graphics tests to this package
instead of android.graphics.cts. It also allows using BitmapComparers.

Modelled after the jni library in CtsGraphicsTestCases. Includes a
slightly modified version of NativeTestHelpers. This version creates a
custom AssertionError, because CtsUiRenderingTestCases does not have the
same legacy exemption as CtsGraphicsTestCases to call the private
constructor "AssertionError(String)". This allows passing a C string to
JNI's ThrowNew to create the AssertionError.

Change-Id: Ic93f03280320332c24e600a1fd7641e4042f850b
6 files changed