Opt host darwin libcxx out of LLD am: bf9a0bcb47

Original change: https://android-review.googlesource.com/c/platform/external/libcxx/+/2133262

Change-Id: Iac06da3537ddc9813be688e433c5cfa1f470e0cb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>