[automerge] Instrumentation: Wait for finish when injecting pointer events 2p: 8e03ce9a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17654828

Bug: 228203157
Bug: 228201593
Change-Id: Ib76a43b23df1418413d7c50f555073206a9843f3