android_jni: Add proguard rules for instrumented tests

GOOGLE_INTERNAL_CL: 524966138
diff --git a/android_jni/avifandroidjni/android-test-proguard-rules.pro b/android_jni/avifandroidjni/android-test-proguard-rules.pro
new file mode 100644
index 0000000..047e1c5
--- /dev/null
+++ b/android_jni/avifandroidjni/android-test-proguard-rules.pro
@@ -0,0 +1,10 @@
+# Proguard rules for the JNI instrumentation tests.
+
+# These classes are needed by the instrumentation testing framework. Keep them
+# unobfuscated.
+-keep class org.aomedia.avif.android.StillImageTest {
+  *;
+}
+-keep class org.aomedia.avif.android.AnimatedImageTest {
+  *;
+}