Merge "Revert "Turn on LTO for libc++.so"" am: d3d779a3ff am: bc7c3e730b

Original change: https://android-review.googlesource.com/c/platform/external/libcxx/+/2644890

Change-Id: I4681b42ebc2be1c82710e138d8f97d1b94b33e2b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>