Add CTS tests to assert invariants around shim apex

* Assert that what we consider a proper shim apex can be installed.
* Assert that offending shim apexes will be rejected.
* I've put it into separate test class because they are conceptually
  different from CTS tests for staged installs.

Test: atest CtsStagedInstallHostTestCases
Bug: 128625955
Change-Id: I0814c17f055dbe3be04946e487748dc4c8c345b6
9 files changed