Use single source of truth for CDM associations

The single source of thruth for state of the cdm associations is
cdm.getAllAssociations. The callback for onAssociationsChanged can have
an already stale list of associations, so removing all associations when
some have just been created will destroy recently created virtual
devices.
Also added some logs for virtual device creation and closure.
This fixes flakiness for CTS tests involving virtual devices, since this
is mostly applicable to tests that create and close virtual devices as
part of the setup and cleanup.

Bug: 443003159 (and many more)
Test: atest VirtualDeviceImeTest VirtualDevicePowerTest
Flag: EXEMPT BUGFIX
Change-Id: Ic162f8c1bbf402d4ce60e190fffcea7f077881a8