DexFile: Add an API to query oat file status.

Adds DexFile.getDexFileStatus(path), which returns an opaque,
human-readable string representation of the oat file status. This
representation isn't guaranteed to be stable and can change from
release to release.

bug: 27494108

(cherry picked from commit cd7e7f78b8e97c1f6419f3f44e0d5fdc6eddfdc6)

Change-Id: If6997f7d28d022e118ffea1eec6183841577a637
3 files changed