microdroid: apk is mounted via apkdmverity

In microdroid, APK and its idsig is used to dm-verity mount before
zipfuse mounts it into a filesystem.

Bug: 190343842
Test: MicrodroidHostTestCases
Change-Id: Icd48fb823eabc087c0266e46f9b3d302e90fd208
8 files changed