Add a copy of debug policy to GSI system image Bug: 188067818 Test: Flash RQ2A.201207.001 bramble-user with debug ramdisk & flash gsi_arm64-user from master, device can boot and `adb root` works Change-Id: I37ef02628b8635e88a9e8ef917da71c8957c4be1 Merged-In: I37ef02628b8635e88a9e8ef917da71c8957c4be1 (cherry picked from commit c329a3a362bdbbc4ebe1123b1d9e835ed68a4b7d)