It casued some runtimes builds to fail with cmake error
No target "libcxx-abi-static"
see code review.
> When in-tree libcxx is selected as the sanitizer C++ ABI, use
> libcxx-abi-* targets rather than libcxxabi and libunwind directly.
>
> Differential Revision: https://reviews.llvm.org/D134855
This reverts commit 414f9b7d2f.