Opt host darwin libcxx out of LLD am: bf9a0bcb47 am: 7063e2d08e

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

Change-Id: I7f0f57e3fc06d0b4634f071aa6dd49a4f79e1745
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>