Merge "Add toString for SRVCC state" am: aac5467d8a am: 4b60ae98d3

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2528706

Change-Id: I59de8a46da9795447d8fbb2203b1b00af28a1a23
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>