Fix AccountManagerServiceTest

Bug: 226979591

AccountManagerServiceTest fails because a PropertyInvalidatedCache
tries to set a system property.  This change puts the caches in test
mode so the test can run.

The change uses the legacy PropertyInvalidatedCache to match a change
that has already gone into master.

Test:
 * atest FrameworksServicesTests:AccountManagerServiceTest

Change-Id: I960120f00290968b4d48ceecd71b22bc8c548e0c