Merge "Define FEATURE_TELEPHONY_IMS_SINGLE_REGISTRATION feature" am: 8cb6d95803

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1564832

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I71d036a1a33aff8097225877bd76c1950156e1bc