Update build-tools to ab/4051621
am: 01920bfb3c

Change-Id: I69a478b8e7a95aeae1dac897337d7636a8f2a05b
tree: 99e76231fab7582e6952ca8dc170d04f857822de
  1. darwin-x86/
  2. linux-x86/
  3. build-prebuilts.sh
  4. manifest.xml