Fix ApfTest

By adding missing so file to Android.mk.

Test: runtest -x frameworks/base/tests/net/java/android/net/apf/ApfTest.java
Change-Id: If13a52845e0cc70a27ca6eeb976a14f91c7146ea
diff --git a/tests/net/Android.mk b/tests/net/Android.mk
index 24524e3..4907894 100644
--- a/tests/net/Android.mk
+++ b/tests/net/Android.mk
@@ -37,6 +37,7 @@
     libc++ \
     libcrypto \
     libcutils \
+    libdexfile \
     libframeworksnettestsjni \
     libhidl-gen-utils \
     libhidlbase \