llvm_tools: add fetch_cq_size_diff

This script exists to fetch image size diffs, primarily for filling out
the Mage's test matrix.

BUG=b:316172272
TEST=Ran the script on an arbitrary CL.

Change-Id: I9b87d8ac6948cd63de8fdceec8c1d9b1dd59ad55
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/5154133
Reviewed-by: Bob Haarman <inglorion@chromium.org>
Commit-Queue: George Burgess <gbiv@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>
1 file changed