Support to extract JNI libs from prebuilt APK

Use LOCAL_PREBUILT_JNI_LIBS to install prebuilt JNI libraries extracted
from the prebuilt apk, or prebuilts as source, to the app specific lib path.
LOCAL_PREBUILT_JNI_LIBS accepts 2 kinds of files:
- Files like @path/to/libfoo.so (path inside the apk) are JNI libs
  extracted from the prebuilt apk. In this case, all embedded JNI libs
  inside the prebuilt apk are stripped.
- Files like path/to/libfoo.so (path relative to LOCAL_PATH) are
  prebuilts in the source tree.

Those prebuilt JNI libs are not defined as modules in the build system,
so this works around possible module name conflict.

Bug: 13170859
Change-Id: I91bb844cc11b3621a85733bc7e8910f168957ef0