Add com.android.resolv-file_contexts to /system/sepolicy/apex

Gathering file contexts for all APEXes there for easier auditing.

Test: m com.android.resolv
Bug: 119527674
Change-Id: I0f06c21c77f4b537e7c7d590204569f4531b5302

apex/com.android.resolv-file_contexts

+(/.*)?                u:object_r:system_file:s0
+/manifest\.json   u:object_r:system_file:s0
+/lib(64)?(/.*)  u:object_r:system_lib_file:s0