Merge "Remove ndk_platform backend. Use the ndk backend." into sc-dev-plus-aosp am: 5e6543130b am: bc35718b86

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/15498074

Change-Id: If0cb1a754159ee2a2b0cc669abf9b4e6eef025a1