Revert "[libcxxabi] Use cxx-headers target to consume libcxx headers"

This reverts commit 72728e12806ae4f85c7ab79b92f2d1c20981d596
which broke libcxxabi tests under the runtimes build.

GitOrigin-RevId: 74ed5124bae163c2046d589026cf17f4fa71f6f4
3 files changed