Move BatteryServiceTest to HealthServiceWrapperTest.

Moving the file in this commit so that git recognizes
that the file is moved, not deleted then created.

Test: none (note: this cannot be built. See next CL that
      correctly fix this.)
Bug: 177269435
Change-Id: I3c41ba1571c30a912b558dac4f1aaf8f1b5c5b61