Split out storage tests, get them running again.

While working on storage tests, it turns out that several tests
were silently not being run.  (!!)  At some point the instrumentation
framework started ignoring methods that dind't start with the "test"
prefix, which resulted in silent success; ouch.

To fix this, split the one-off behaviors into separate test files,
and run them in their new location with "test" prefixes.

Split external storage tests into their own separate host test suite,
and clean up various invocation methods to call through to unified
Utils versions.  Start adding skeleton test for adoptable storage.

Bug: 22633097
Change-Id: I5b8ffade970ff0086c95ddd5cd28fc069826a21a
14 files changed