Add vignette filter to Image Processing test

Add a vignette filter, mostly based on the GLSL version in
android.filterpacks.imageproc.VignetteFilter but with more input options.

Change-Id: I6f38a0ca09d35566104ec8e8523548399b8704a0
diff --git a/tests/RenderScriptTests/ImageProcessing/src/com/android/rs/image/vignette_relaxed.rs b/tests/RenderScriptTests/ImageProcessing/src/com/android/rs/image/vignette_relaxed.rs
new file mode 100644
index 0000000..8e47ea9
--- /dev/null
+++ b/tests/RenderScriptTests/ImageProcessing/src/com/android/rs/image/vignette_relaxed.rs
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma version(1)
+#pragma rs java_package_name(com.android.rs.image)
+#pragma rs_fp_relaxed
+
+#include "vignette.rsh"
+