Use ArrayMap instead of HashMap in transitions

The new ArrayMap class is more efficient for small collections.
Transitions use maps all over the place to collect/use property
values in setting up the transition animations. Changing to ArrayMap
should be more efficient, especially in terms of memory allocations
and GCs.

Issue #9276256 Transitions: Reduce memory allocations

Change-Id: I07b7d4ba68d5a207808eca11943aa3578fa90e3e