health storage: refactor common code for test am: 571f926977 am: a3a71464e6 am: 5cf01df3c1

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/1553198

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ib2fafb5c652f56c149a5fe62d413887b669e1a5d