Put reference filters on 'git ls-remote'.

This saves time and bandwidth expecially as the number of references
scale up with uploaded CLs.

BUG=None
TEST=CQ passes

Change-Id: Idf0e9eea97bc533ec21f29cfd8267a260f7322ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2302949
Reviewed-by: Tiancong Wang <tcwang@google.com>
Commit-Queue: Allen Webb <allenwebb@google.com>
Tested-by: Allen Webb <allenwebb@google.com>
2 files changed