Pass -fuse-ld=bfd when use_mold=true

This fixes builds for those use cog (not sure why it's not universal).

clang++: error: invalid linker name in argument '--ld-path=../../buildtools/third_party/mold/mold_wrapper.py'
build failed

Bug: 40208899, 509543574
Change-Id: Ifbcba1c3ac2fd5eeaaabc4bb3944ec5f4521f07b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7813498
Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Owners-Override: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Sam Maier <smaier@google.com>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1626131}
NOKEYCHECK=True
GitOrigin-RevId: 563140cf6ca268069f08ce02e791222ba4c7a8cc