Update tests for updated storage design.

Confirms that older apps aren't placed in sandbox, newer apps are
placed in sandbox by default, and that they can opt-out using the
new manifest flag.

Bug: 129487770
Test: atest android.appsecurity.cts.ExternalStorageHostTest
Exempt-From-Owner-Approval: trivial tests
Change-Id: Ib78f6891a342ce76488bdeb48d0893b83615210a
6 files changed