Add lookupOrCreateWeak to ObjectManager

This looks for an attached object on the binder, attempts to promote it,
and returns the object if it could be promoted.
Otherwise, it will create a new object and attach it to the binder.

Test: atest binderUnitTest aidl_integration_test
Bug: 220141324
Change-Id: I2c8baa211300fa3ada50f2b2c93862f8c968be26