Add coverage related binaries to clang_linux asset

Add --depth 1 to the git clone commands to speed up the creation,
since we don't need all of the history ever to build.

Bug: skia:7080
Change-Id: Idcde5657e2097c2dbc259ab29b24d596b5623364
Reviewed-on: https://skia-review.googlesource.com/53481
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
3 files changed