ArrayUtils: rename concatElements() to concat() am: 96abd9452d am: 178682cb12

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2429552

Change-Id: I07f783c8c32f459d6a06a0e97334a4fcd9dae721
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>