Add toolchain/benchmark to the manifest

Bug: http://b/63768402

Test: repo init -m <new_manifest>; repo sync
Change-Id: I19c14d01724e48137dc48ef57fc8d2bf12322c02
1 file changed
tree: 273a2a32877ffd9d09bb9e33b89b1de66ca4362b
  1. GLOBAL-PREUPLOAD.cfg
  2. default.xml