Update clang-tools to ab/6450978 am: 8984d81cea am: 1c3632ca18 am: 87d0a502e3

Change-Id: I374e038845572364b3b92c64e2e6a676c28278c5
tree: bcf6c4afcea8361d677531a3c57dbd3738feec6d
  1. darwin-x86/
  2. linux-x86/
  3. build-prebuilts.sh
  4. manifest.xml