Convert healthd_test to Soong

This makefile is not included before, so it was never built. Also do
the following changes to make sure it works:

- Remove non-existing libhealthd_internal dep
- Add necessary libhealthd_charger dep because it tests AnimationParser
- Since it tests AnimationParser, change its name to
libhealthd_charger_test

Test: run it

Change-Id: If7f91de4b910024f27d09a25ca801e67b98221db