Revert "[CMake] Use libcxx-abi-* targets for in-tree sanitizer C++ ABI"

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 414f9b7d.