Update LLVM_PREBUILT_VERSION to r349610 am: 654311e094
am: 5e53618749

Change-Id: I17c18f6f1e656d0c66305f82d48aaec7f959b886
tree: d28dc0d674ed13db838005e36c21ed2b495208c8
  1. darwin-x86/
  2. linux-x86/
  3. build-prebuilts.sh
  4. manifest.xml