Merge "Revert "Use platform prebuilts from NDK r23 canary."" am: 3ff884f0a2 am: 865012cd2f am: 1b3650fadf

Original change: https://android-review.googlesource.com/c/platform/prebuilts/ndk/+/1658454

Change-Id: I60610cf18ffd9044e58e1419cf251b0983e63c82
tree: 5374a9c1afcefb70d830e9eb595053f101643123
  1. r21/
  2. r23/
  3. Android.bp
  4. Android.mk
  5. CleanSpec.mk
  6. NOTICE
  7. pylintrc
  8. update.py