Merge "Prevent starting split pending transition when it exists" into udc-dev...

Merge "Prevent starting split pending transition when it exists" into udc-dev am: 56557a6f am: 2d77e53b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22221903



Change-Id: Ie72161783c14a96729aec7bf728a82330642d657
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>