Disable binder caches in unit tests

Bug: 152451909

Unit tests often execute server code in the context if a test process.
Such a process does not have the same permissions as formal system
processes.  In particular, such a process does not have permission to
invalidate binder caches.

This change disables all binder cache code in the current process.
This means caching is disabled and invalidation never occurs.  There
are no permission violations and the test process is also unable to
affect (through cache invalidation) the actual system processes.

Test: Ran a list of atests.  Two had security violations before the
change but were okay after the change:
 * FrameworksServicesTests
 * UserSystemPackageInstallerTest
 Ran additional tests to verify no regressions:
 * PlatformScenarioTests
 * PtsChreTestCases
 * BluetoothInstrumentationTests
 * UserLifecycleTests

Change-Id: I011ee1eb39b2d52c69b6d5164b64f7418d2bbdd4